Llansadwrn (Anglesey) Weather:
Monthly and Annual
Summary for 2002
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Llansadwrn (Anglesey) Weather:
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The first 11 days were dry and coldest, The latter part of the month was wet, bringing the rainfall up to average, and windy. Overall it was very mild making it one the warmest on record.
The mean temperature was 6.8C (+1.5) and tied with 1989 as the warmest January in records since 1979. The mean maximum 9.3C (+1.5) was the warmest on record but the few cold days at the beginning kept the mean minimum to the 3rd warmest at 4.2C (+1.5) as both 1989 and 1990 were 4.5C. The warmest day was on the 12th with 12.3C but 14 days had maximums of 10C or more. The coldest day was on the 2nd with a minimum of -2.3C and -7.3C on the ground. There were only 4 days (-1.6) with airfrost being frost-free from the 12 - 31st, while there were 11 days (-3.5) with ground frosts. Soil temperatures were above average with the mean at 30 cm 5.6C (+0.7) and there were 18 days above 5.6C (the temperature thought necessary for plant growth). Evaporation was above average for January with the Piche evaporimeter showing 34.7 mls (+7.3) and the lysimeter a PE of 8.1 mm (+2.3). Soils were moist, or waterlogged all month and the water balance was in excess by 91 mm.
Rainfall of 99.1 mm was very close to average but most was in the latter part of the month and made up of 4 heavy falls. Only 7.4 mm fell in the first 15 days while the rest 91.7 mm fell at the end. There were 4 falls of 10 mm, or more, 15.3 mm on the 16th, 17.8 mm on the 25th and the largest, 11.0 mm on the 29th and 16.8 mm on the 31st. There were only 3 dry days (-5.5) but rain days (0.2 mm or more) 18 and wet days (1.0 mm or more) 14 were close to average. It was drier in the NW of the island with Valley reporting 70.8 mm 91% of average. (
It was a windy month particularly in the latter part. There were 9 days of gales comprising 4 consecutive days 26 - 29th. Mean wind speeds (mws) reported at Valley for the period 11 - 31st were all in excess of 16 mph. The highest mws was on the 28th with 35 mph that day also had the highest gust of 65 mph.
It was a poor month for sunshine with the sunniest day on the 1st with 6.1h at Valley. There were 18 days with 0.2h or less (12 were sunless). In all there were 50.7h sunshine 85% of average.
Thunder was heard on the 26th during passage of an active cold front. Ice pellets fell on the 15th, 22nd and 30th.
The month resumed the storms of January and remained unsettled and generally mild but very wet.
; "Click for graph of February rainfall in Llansadwrn 1928-2002: © 2002 D.Perkins."){kind=small}
Rainfall of 187.7 mm was 198% of the 10-y average but 250% of the 30-y average and long-term averages. In records back to 1928 it was necessary to look at 1958 to find a wetter February. In 1958 the then 2 Llansadwrn stations reported an average of 192.9 mm (196.1 mm and 189.7 mm). It easily exceeded the 143.4 mm of February 2000, the wettest year on record, and also beat the rain of 1990 that had 180.5 mm both recorded at this station. There were 10 falls of 5 mm or more (+3.1) 10 of which were over 10 mm. The largest was 33.7 mm on the 10th that fell over 12.8 h an average of 2.6 mm per hour. There were 22 (+2.9) rain days (0.2 mm or more) and 16 (+1.7) wet days (1.0 mm or more). There were, surprisingly, 4 (-1.9) dry days all around the quiet middle of the month with 11 - 16th having a total of only 1.3 mm. The histogram of monthly rainfall in February 1928 - 2002 (differences from mean) shows that in the first 62 years there were only 5 years when the anomaly was >50 mm, whereas there have been 5 in the last 13 years. An indication of the relative wetness of recent years. Evaporation was near the average with the Piche on 28.9 ml (+2.6) and PE on 11.9 mm (+1.3 mm), but there was a water balance of 177 mm (+79 mm) that was evident seeing the waterlogged fields, full flowing streams and flooding in the area.
It was another very windy month with the first 13 days almost constantly strong to gale-force winds. In this period there were gales on 1 - 4th and 7th. The 1st and 2nd were strongest when Valley reported force 9 and gusts of 70 mph and at Abersoch force 10 with gusts up to 82 mph on the 1st. The end of the month saw a return to strong to gale-force winds from 18 - 28th with gales on 20th and 26 - 27th.
; "Click for graph of daily mean temperatures: © 2002 D.Perkins."){kind=small}
It was another mild month with the mean temperature of 6.7C 1.0C above the 10-y average. Mean maximum 9.3C and mean minimum 4.1C were similarly +0.9 and +1.0). On the 30-y 1971-2000 average the mean was 1.4C above average an indication of the relative warmth of recent years. Temperatures were almost identical to those of January and, at first, continued the well-above average figures. Towards the end of the month temperatures returned closer to the average. There was no air frost the lowest was 0.1C on the on the 21st that also saw the lowest grass minimum of -4.4C. It was the first February without air frost since 1995 which is the only other in records since 1979. There were 12 ground frosts close to the average.
There were flurries of snow on the 23rd and 28th with sleet on the 26th. There were 6 days with small hail (< 5 mm) and large hail up to 10 mm diameter fell on the 22nd that also saw frequent showers of snow pellets and ice pellets. No thunder was heard during the month.
It was a dry month with 39.0 mm rain that was 48% of average but not quite as dry as March 2001 (35.0 mm). It ranked 15th driest in records back to 1928. There were 13 (+4.3) dry days spread through the month. The wettest day was on the 30th with 8.6 mm closely followed by the 8th with 7.7 mm. These were the only days with rainfall of more than 5 mm (-3.4). There were 15 (-2.4) rain days (0.2 mm or more) and 10 (-2.5) wet days (1.0 mm or more). Evaporation measured by the Piche evaporimeter was 37.9 ml (+6.7) and was the highest measured in March since records began in 1966. PE (potential evapotranspiration) was 23.2 mm and PWB (potential water balance) only 15.8 mm. With the drier weather local farmers were able to get on with ploughing and sowing their barley fields.
; "Click for histogram of mean temperature anomaly in March 1979-2002. © 2002 D.Perkins."){kind=small}
The third successive month this year with warmer than average temperatures. The mean maximum of 11.2C was the most marked being some 1.2C above average and ranked 4th in records since 1979. The mean minimum 4.3C (+0.3) was nearer the average and this made the mean 7.8C (+0.8C) and ranked 5th warmest. There is a trend (not statistically significant) towards warmer Marches, in recent years, despite the odd colder one. There was only 1 air frost (-0.7C), 1 below the average, on the 2nd that also saw the lowest grass minimum of -2.7C. In all there were 9 ground frosts near the average. Maximums did rather well with 22 days with 10C, or more and 7 of 14C, or more. I thought the the month would not see 15C, or more, but a very pleasant day on the 29th reached 16.0C in the afternoon. It was not unusual, however, as it has been exceeded 6 times in March since 1979, the highest was 20.5C in 1997 on the 11th.
Three days (8 - 10th) of wintry weather brought showers of ice pellets, sleet, fog and a gale with gusts of 60 mph on the 10th. No thunder was heard in the month. Sunshine, particularly at the end of the month 26 - 29th that each had 10h, or more, brought the total recorded at Valley to 135 h (+15). Sunniest day was on the 28th with 11.2h. Other sunny days (5h or more) were on the outside this spell were on 1, 5, 7, 11, 13, 16, 21, and 30th. There were 8 sunless days and another 3 had 0.2h or less.
The first 3 months of the year (January to March) were the warmest globally since records began in 1860. Worldwide temperatures were 0.7C above the 1961-1990 average. To read about it, and predictions for the year 2080 by the Hadley and Tyndall Centres, go to the BBC pages here. In the UK there have been warmer winters (December to March) such as the one in 1868/69 that had a Central England Temperature (CET) of 6.8C. This last winter had a CET of 5.3C while here at Llansadwrn the mean was 6.2C. The mean January to March in Llansadwrn was 7.1C, but it has been warmer with 7.4C in 1998 and 7.3C in 1990.
Respite from the dry weather at the end of March continued into April with 3 days of rain. This was followed by a spell of settled sunny weather 4 - 16th that had 11 dry days (+3.4), only the 13th and 14th had rain. A wet end to the month brought the rainfall total to 79.1 mm, 105% of the 10y average, but 137% of the 1971 - 2000 average. It was not as wet as 2001, that had 103.8 mm, but was ranked 21st wettest on record since 1928. There have been some wet Aprils with 6 having 100 mm, or more, with 1970 having 142 mm. This April there were 17 (-0.3) days of rain (0.2 mm, or more) and 14 (+0.2) wet days (1.0 mm, or more). There were 7 (+3.4) days with 5.0 mm or more, with 4 days having more than 10 mm. The largest fall of 15.5 mm was on the 29th.
Evaporation measured by the Piche evaporimeter was 47.4 ml (+10.6) and, following the lead of March was the highest measured in April since records began in 1966. There were several windy days, with lower relative humidity than usual, in which more than 2 ml was evaporated. The average evaporation per day in the month was 1.6 ml. Evaporation (PE) measured by lysimeter was below average at 30.6 mm (-9.4 mm). This reflects exposure of the rather different instruments and temperature differences; the Piche is in the screen while the lysimeter is sunk in the ground. Up to the 15th of the month potential water balance (PWB) was -0.8 mm, with the soil surface cracking, but the rain at the end of the month restored it to 48.2 mm. Soils became saturated once more and resulted in local fields having pools of water standing on them on the 30th. Rainfall this year has been 405 mm and with PE 74 mm the potential water balance is 331 mm. It is the 12th wettest first 4 months of the year since 1928, this despite the dry March and beginning of April.
For the 4th successive month this year monthly mean temperatures were above average. The mean 9.0C (+0.4) was warmest since 1999 but was not outstanding and ranked 9th warmest in records since 1979. The mean minimum 5.3C (+0.2) ranked 6th warmest with the highest minimum of 10.2C on the 22nd ranked 4th warmest. The lowest minimum was 1.0C (+0.7), there being no air frosts, on the 15th that also saw the lowest grass minimum of -2.3C (+0.8). The lowest minimum ranked 3rd warmest on record. The number of ground frosts was 5 about 1 below average. The mean maximum 12.7C (+0.5) showed the greatest anomaly but again was not outstanding. Indeed it ranked only 11th warmest with top temperatures remaining rather moderate. The highest maximum was 15.8C (-1.8), 0.2C less than in March, and only the 15.3C of April 2001 was colder.
The end of the month saw a cooler spell with ice pellets falling on the 28th and 29th. No thunder was heard in the month. The end of the month was also windy being strong to gale-force from the 21st to 30th. There was 1 gale on the 28th when a gust of 59 mph was recorded at RAF Valley. The mean wind speed was 14.6 mph a little above the average.
There were sunny days between the 5th and 10th, and on the 15th, 16th and 19th. Sunniest day was on the 15th with 12.4h sunshine while there were only 2 sunless days a further 5 had 1h or less. Total sunshine was 163h 97% of the 10y average.
Rainfall of 61.2 mm (90% of average but 106% of the 1961 - 90 average) fell mainly at the end of the month making it the wettest May since 1999. In the first 16 days 12 were dry and the 3 wet days had only 5.3 mm. In a spell from 17 - 29th it rained every day and accumulated 55.9 mm. But there were only 3 days (-1.6) of 5 mm, or more whereas there were 16 rain days (0.2 mm or more). The largest fall was 13.5 mm while Valley reported 19.2 mm on the 17th. On that day Llansadwrn was in the rain shadow of the Snowdonia Mountains and had only 9.2 mm. Valley's total for the month was large at 69.4 mm (+29%) it being usually drier in the NW corner of the island.
The mean temperature 11.8C was very close to average (+0.1) and just makes May the 5th month in succession to be above average. This value hid the differences from average of the mean maximum 15.2C (-0.5) and mean minimum 11.8 (+0.6). Maximums continued to be low and were the coolest since 1996 and ranked 8th coolest on record since 1979. But there were 2 warm days on the 16th (24.7C, highest of the month) and 17th (21.3C). The minimum of 17.0C, and mean of 19.1C, on the 17th were the warmest in May on record here. The temperature at 04 GMT rose to 20.3C in a Föhn-like wind blowing off the mountains. In the month there were 7 nights when the temperature did not fall below 10C. There was no air frost but there were 2 ground frosts on the 3rd (-0.8C) and 4th (-0.2C). Soil temperatures at 30 cm averaged 13.4C (+0.1).
There was a stormy end to the month with gales on the 20th, 22nd and 24th. Monthly mean wind speed was 16.4 mph with the windiest 31.9 mph recorded on the 24th. On the western side of the island salt blown in on the winds scorched and browned leaves on trees and plants making it look like autumn. Salt was blown right across the island and some exposed edges of woodland in Llansadwrn were also damaged.
Sunshine at Valley was 190.6h (85% of average) with the 2nd - 5th and 10th - 11th the only days with 10h or more. The 4th was the sunniest with 14.0h but there were only 3 days that had 1h or less.
Rainfall this year so far has been 466 mm and ranks 8th wettest on record. Most was early in the year as the spring months (March - May) have been drier with 179 mm (driest since 1997 171 mm) and ranks 30th driest. Spring temperatures have not been outstanding with the mean of 9.5C ranking only 8th warmest.
A warm and sunny on the 1st, a thunderstorm on the 2nd, then downhill all the way with strong winds and gale on the 16th.
The first month of the year with the mean temperature of 13.5C (-0.2) just below average. Despite a mean minimum of 10.3C (+0.3) the low mean maximum, 16.7C (-0.7), was insufficient to give make the mean a 6th successive month above average. It was warmest at the beginning with the highest maximum 22.6C (-3.3) on the 1st. This was the lowest since 1997 (21.7C) and ranked the 6th lowest on 23 years' records). Maximums in the remainder of the month were on the low side. But the coolest day, with a maximum of 13.3C on the 30th, was the warmest since the 13.5C in 1996 ranking 6th. Highest minimum (13.8C) was on the 17th while the lowest 7.3C on the 4th ranked 2nd warmest only beaten by the 7.5C in 1992. The lowest grass minimum of 4.0C also occurred on the 4th.
; "Click for graph of first 6 months rainfall anomaly (January to June) in Llansadwrn (differences from 1929-2002 mean): © 2002 D.Perkins."){kind=small}
Rainfall was 68.8 mm (95%) with the wettest day (the 14th) having 16.7 mm followed by 10.7 mm on the 30th. There were 9 dry days (-3.5) but 18 (+3.6) rain days (0.2 mm, or more). Wet days numbered 13 (+3.3) (1.0 mm, or more) with 5 days of 5 mm, or more that were closer to the average (+0.7). Rainfall in the 6 months (Jan - June) totalled 534.9 mm (+85.2 mm on LTA). It exceeds the 515.9 mm that had accrued in 2000, the wettest year on record. In recent years both 1999 (599.0 mm) and 1998 (600.5 mm) were larger but 2002 does rank 7th wettest on record here since 1928. The wettest first 6 months was in 1958 with 623.7 mm but at the end of the year 1263.3 mm had accumulated ranking it only 9th overall. The first 6 months rainfall anomalies (differences from the 1929 - 2002 mean) are shown in the histogram. In the last 14 half-years there have been 9 with a positive anomaly >50 mm whereas there were only 9 in the previous 60 half-years! Could such an increase of frequency be taken as an indication that our climate is changing or, at least, are we experiencing a wetter phase? Looking at the drier than average half-years in the last 14 there were 3 with a negative anomaly of >50 mm whereas there were 19 in the previous 60 half-years. But 11 of these were in the 20 years of the 70's and 80's, whereas in the previous 30 half-years there were only 8. It seems that we are into a spell of wetter than average first half-years. Who can tell how long it will last?
It was a windy month particularly around the 9th to the 17th with strong to gale-force winds and a gale here on the 16th. The mean wind speed at RAF Valley was 16.5 mph the highest in June since 1974 and 3rd highest on record. On 23 days gusts of 25 mph or more were recorded with a maximum of 50 mph on the 17th.
June, along with May and July, have one of the largest evaporation totals. This year with, cool maximum temperatures, PE (potential evapotranspiration) was 61.1 mm (-15.6) while by the Piche evaporimeter was 46.7 mls was (+2.6).
There was a thunderstorm on the 2nd but no hail was seen. Wet deposition of light-coloured dust was seen on the 2nd, 5th and 13/14th all seem to have been of N African origin.
Cloud cover at 0900 GMT was 85%, the highest in the year so far, just exceeding January and February that had 83%. June last year (2001) also was dull with a cover of 85% and this was only exceeded by November! At RAF Valley 160.2h (-38.1) sunshine were recorded, the lowest since 1987, only 78% of the 1961-90 average. It is cloudier in Llansadwrn by about 12 - 15% because of the closeness to the mainland mountains so it has been a pretty dull month. Sunniest day was the 1st with 11.5h at Valley and 7 were sunless or had 1h or less.
The second month with a below average mean temperature of 14.7C (-0.9) and the third month for the mean maximum 18.0C (-1.2). The mean and mean maximum, both coolest since 1998, ranked 7th coolest on 24 years' records. For the first month the mean minimum 11.4C (-0.6) was also below average. The warmest day was 23.0C (-1.8) on the 15th, ranking 6th lowest, and there were just 6 warm days that reached 20C, or more, including a spell of 4 days 26 - 29th. Lowest minimum was 8.3C on the 18th. The highest minimum of 16.6C was the 6th warmest on record the warmest in July being the 17.6C seen in 1995. The lowest grass minimum of 5.2C occurred on the 13th and 24th.
Rainfall of 57.5 mm was 94% of average with the wettest day having 13.8 mm on the 4th. There were 11 dry days (-0.5) and 13 rain days, 0.2 mm or less, that was 2 below average. Number of wet days, 1.0 mm or more, were 11 (-0.9) and days with 5 mm, or more, were 4 (-0.2).
Evaporation totals for the month have been low with PE (potential evapotranspiration) of 47.8 mm (-26.1) the lowest in July on record since 1997. PWB (potential water balance) was 9.7 mm and 17.8 mm above average. Normally a water deficit can be expected at this time of year. Similarly evaporation from the Piche evaporimeter was only 38.6 mls and this just 0.1 mls above the lowest observed in 1996. The low evaporation totals were a reflection of the cool temperatures, lower than average wind speeds and high relative humidity (mean 85% at 09 GMT) seen in the month.
It was another dull month with a mean cloud cover at 0900 GMT of 83%. Sunshine at Valley 126.1 h was only 65% of average. There were 5 sunless days and another 6 with < 1 h. Sunniest day was the 21st with 11.7 h and another 4 had 10 h, or more. It was the 3rd dullest July in Anglesey on record since 1913. Fog was seen on 3 days but none recorded here at 0900 GMT although Valley, near the coast at 10m reported 5 days.
There were no days with gales, thunder, or hail.
A wet month with 110.2 mm (the 2nd wettest of the year) less than the 132.4 mm that fell in August 2000, the wettest year on record, but was ranked 23rd wettest on 75 years' records. The summer months ended with a total of 236.5 mm rain, close to the long-term average, and ranked only 33rd wettest. In August there were 2 very wet days: on the 1st 36.5 mm was the largest fall of the year, so far and, on the 17th there was another 25.3 mm. Evaporation from the Piche tube was only 29.9 ml, the lowest in August on 7 years' records, and PE measured by the lysimeter only 36.9 mm. It was not surprising that there was a healthy water balance of 73.3 mm and no watering of the vegetables on the garden plot had to be done. The damp weather caused problems for local farmers who were well behind with grass cutting and wilting for silage and haymaking. Hay was made, in the field next to the weather station, after turning for 3 days to dry heavy dew. There were 8 dry days (-4.1) and 17 (1.8) rain days, 0.2 mm or more, in the month. Wet days, 1.0 mm or more, numbered 14 (+2.3) while those over 5 mm were about average at 6.
It was the 3rd month of summer that had a mean temperature (15.5C) below average (-0.3). The main reason was again the rather low maximum temperatures. The highest of 23.0C was on the 17th and was the lowest since the 21.1C in 1992 and the 4th lowest on 24 years' records. This made the summer mean maximum 17.8C, the lowest since the 17.7C in 1998 and ranked the 5th lowest on record.
It was a quiet month was no gales and 8 calm records at 0900 GMT. The lack of wind spoilt the racing in the Menai Strait Regatta's second week at the beginning of the month. The windiest was at the end of the month, on the 30th, when SW'ly winds reached force 7 and, in heavy rain, forced 30 mph speed restrictions on the Britannia Bridge that brought holiday traffic to a crawl in long tailbacks.
No thunder was heard but some ice pellets were spotted falling in a heavy shower on the 22nd. Hail in August here is rare with the only other occurrences, on 24-y records, being 1 in 1982 and 2 in 2000.
A dry month with only 23.0 mm and the driest September since 1986 (that had 11.7 mm) and ranked 2nd driest on record back to 1928. The long-term September average (1928 - 2002) is 100 mm and, including 2002, there have been 10 Septembers with ; "Click for graph of September rainfall anomalies in Llansadwrn 1928-2002: © 2002 D.Perkins."){kind=small}
negative anomalies of 50 mm, or more. These are 1933 (-63), 1938 (-52), 1939 (-69), 1941 (-67), 1959 (-73), 1969 (-68), 1972 (-67), 1986 (-88), 1989 (-75) and 2002 (-75). It was also the driest of ANY month since the 6.6 mm in January 1997, but May 1998 with 25.3 mm and July 1999 with 26.1 mm were close contenders. There have only been 29 drier months out of nearly 900 since records started here. There were 20 dry days this +10.9 on the average. Rain days, 0.2 mm or more, were 8 (-8.1) and wet days, 1.0 mm or more, 5 (-8.3 mm). There were only 2 days (-4.7) with 5 mm or more; 5.3 mm on the 6th and 12.0 mm, on the 9th that was the wettest day. There were only 17.0 h of rainfall duration, falls >0.1 mm / hr. Relative humidity averaged 84% with the lowest of 56% seen on the 11th and 28th. With light winds evaporation measured by the Piche evaporimeter was 37.7 ml a little below the average of 18.1 ml. Potential evapotranspiration PE was only 27.3 mm (-13.5), less than the 37.1 mm seen in 2001, and ranked 2nd to 2000 with 16.1 mm. Despite this it resulted in the first negative monthly water balance (-4.3 mm) of the year.
After 3 months of below average temperatures September was above with the mean 14.5C (+0.8). This, along with 1991, was ranked 2nd warmest on 24-y records beaten only by the 15.0C in 1999. The mean maximum was 18.1C (+1.1) and the mean minimum 10.8C (+0.5). The warmest day was on the 12th with 23.5C and there were 8 days of 20C, or more, including a spell of 3 days on 11 - 13th. The lowest maximum 14.9C, on both the 16th and 19th, was the highest in September on 24-y records. It was also the highest of the year. The lowest minimum was 7.2C on the 24th that also saw the lowest grass minimum of 3.2C.
It was another quiet month with mostly light and variable winds and no gales. No thunder was heard but large ice pellets fell in heavy rain on the 9th, the first in September since 1998.
Cloud cover at 0900 GMT averaged 68% and was the second most cloud-free month of the year, March averaged 67%. Valley reported 162 h (+9) sunshine but was +19 h on the 30 y average. The were 6 days of 10 h, or more with the sunniest day on the 1st. There were 6 days with <1 h sunshine 4 of them being sunless.
The first 10 days were warm and dry before it turned wet and colder with a stormy finish.
The first 10 days of the month continued September's warmth and dryness. On the 1st the maximum of 22.2C was the warmest in October since 1997 (24.0C) and ranked 5th warmest. Also the day's mean 17.3C ranked 3rd highest and warmest since 1990 (19.0C). In contrast the lowest maximum 8.9C (ranked 7th) was the coolest since 1992 that had 7.4C. While the monthly mean maximum 13.6C was -0.3 of average the first 10 days averaged 17.2C the rest of the month averaged 12.0C. The mean minimum for the month was 7.4C and was -0.5 but in the first 10 days it averaged 10.3C wile the rest averaged 6.0C. The lowest minimum 2.0C was on the 24th that also saw the lowest grass minimum of -1.8C, 1 of the 2 days with ground frost in the month (the other was on the 19th with -1.4C). The monthly mean was 10.5C (-0.4) with the lowest 7.0C on the 18th. The first 10 days averaged 13.7C while the rest averaged 9.0C. The mean soil temperature of 12.3C was 0.3 above average but saw a reduction from 15.2C on the 1st to 9.8C on the 31st.Rainfall followed a similar pattern. The first 10 days saw only 6.2 mm with the remainder 157.7 mm fell at the end of the month. The total 163.9 mm was 147% of average. It ranked the 10th wettest October on record, since 1928 and wettest since 2000 (with 223.0 mm the wettest year). With 889.5 mm so far the year ranks only 20th. Wettest day was on the 20th with 33.2 mm but 21.6 mm also fell on the 11th and 19.6 mm on the 13th. There were 12 (+4.0) days, with 5 mm or more. Rain days (0.2 mm, or more) were 23 (+3.6) while wet days (1.0 mm, or more) numbered 15 (-1.1). There were only 5 dry days, all in the first 10 days of the month.
There were 5 days with hail (all types) the most on record in October since 1979 (1992 had 4) but no thunder was heard. The month had mainly light winds with 6 mornings calm at 0900 GMT. Winds were predominately NE - S 15 days compared with SW - N with 10 days. The exception was overnight on the 26/27th when strong wind before midnight became gale to severe gale by the following morning. On the morning of the 27th the mean wind speed at Valley reached over 58 mph with an of average 31.1 mph. But over the month the mean wind speed was 11.1 mph (-2.7). The wind was very gusty (82 mph was seen at Valley while 104 mph was recorded at Holyhead Harbour) and caused damage to property and brought down many trees and power lines. Over 80 trees were damaged or uprooted at Bodnant Garden in the Conwy Valley.
Sunshine at Valley was 96.4 h (-19). Sunniest day was on the 3rd and there were 6 sunless days and a further 7 days had 1 h or less.
Thunder was not heard in the month but there were 3 days that had ice pellets and 2 days with 5 mm hail. Number of days with hail of all types 5 was 3.6 above average.
; "Click for histogram of mean temperature anomaly in November 1979-2002. © 2002 D.Perkins."){kind=small}
The first 13 days of the month were mild with the mean maximum 12.6C and minimum 7.3C. While these, especially the maximum, compare favourably with the the monthly means (30 days) of the warmest November on record in 1994 (max 12.4C and min 7.9C), the first 13 days were warmer with a mean maximum of 13.3C and minimum of 8.2C. The month ended with a mean maximum of 11.8C (+1.3), a mean minimum of 6.7C (+1.5) with the mean 9.3C (+1.4) some way behind 1994 but ranking 2nd on record since 1979. There were only 4 days on which the maximum was less than 10C but in 1994 only the last day fell to 8.4C. In 1994 there were 5 days on which the minimum was 10C, or more, whereas in 2002 there were none. Means in 1994 were 10C or more on 19 days whereas in 2002 there were only 9. This shows how remarkably mild was November 1994; November 2002, ranked 2nd, falls far short.
November 1994 and 2002 compared
1994 2002 1994 2002
days days t C t C
Max >= 10C 29 26 Mean max 12.4 * 11.8
Min >= 10C 5 0 Hi max 16.0 15.0
Min >= 5C 26 25 Mean min 7.9 * 6.7
Mean >= 10C 19 9 Lo min 2.8 3.2 *
Mean >= 5C 26 30 Grass min 5.7 * 3.4
Air frosts 0 0 Soil 30 cm 10.3 * 9.4
Ground frosts 3 + 4 Rain mm 106.3 184.6
+ Lowest on record * Warmest on record
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The period 11 October to 11 November was particularly wet. Total rainfall was 275 mm and this just behind the same period in 2000, the wettest year on record, that had 285 mm. The month of November with 184.6 mm was wet, 149% of average and ranking 9th on record since 1928. It was the wettest November since 2000 that had 250.5 mm but it is than necessary to go back to 1972 with 197.9 mm to find the next. There were only 3 dry days (-1.7) and 26 rain days (0.2 mm or more). There were 19 wet days (1.0 mm or more) and 11 days had 5.0 mm or more. The wettest day (09 - 09 GMT) was on the 8th with 25.5 mm but if the 24-h period is (18 - 18 GMT) then 40.0 mm fell on the 8th (not far behind Capel Curig that had 51 mm) and 30.9 mm on the 28th that was the largest reported (Aberdaron had 21.3 mm). November 1994 with 106.3 mm (83%) rainfall was below average and drier than 2002. The middle of the month saw an unusually high number (8 at 09 GMT) of wind (and weather) from the SE. When this happens we are in the lee of the Snowdonia Mountains; there is a rain shadow effect and rainfall is lower than normal. The Isle of Man to the N had more rainfall as well as places to the S and SW of England, and parts of South Wales. Total rainfall for the year here so far is 1074.1 mm and running 12% above LTA but behind the 1330.3 mm accumulated in 2000 the wettest on record.
Small ice pellets fell on the 12th and thunder and lightning occurred in NW Anglesey at Malltraeth and Valley. Thunder was heard and lightning seen in Llansadwrn on the 28th when there were falls of small ice pellets in the early hours and and hail >5 mm in the afternoon.
After a wet 5 days it turned drier and cooler with airfrost on the 18th and 19th. The end of the month was wet and very mild.
Rainfall for the month 113.1 mm finished on the long-term average. The 10 y average was 90%, recent Decembers have been very wet, whereas the 1971 - 2000 average was 115%. There were 9 (+3.1) dry days and 20 (-1.2) rain days (0.2 mm or more). Wet days (1.0 mm or more) were 16 while there were 9 days (+3.1 mm) with 5 mm or more. This seems to continue the recent trend towards heavier daily falls of rain. Largest fall was 22.8 mm on the 29th with 13.2 mm on the 25th.
It was a generally mild month with the mean on 6.0C (+0.5). Maximum temperatures were however on the average at 7.9C. The 23rd saw very mild temperatures in a warm S'ly airflow 13.2C was recorded here just before 0900 GMT and 15.2C soon after. These were the highest temperatures seen in December at this station easily beating the previous 14.5C seen on 2 December 1994. It was warm especially in the W in places as far apart as Scilly (13C), Chivenor (14C), Trawscoed (14C) and Skye (12C). But temperatures were highest in N Wales, (Llanbedr 15C) and Anglesey (Pentraeth 15.5C) enhanced by a Föhn-effect. The highest I spotted was 15.9C recorded by the AWS in Llanberis at 0930 GMT, but you had to be in the right place because Bangor Harbour only saw 12C and Valley 13C.
The mean minimum was 4.0C (+1.0) there being few cold (and clear) nights. The 18 - 19th were an exception being the only 2 (-4.0) with slight airfrost. The coldest was the 18th with -0.7C this (+1.8C). There were more ground frosts 12 (-2.6) but even these were below average. The lowest grass minimum was on the 18th with -5.4C (+1.2) and again above average. There were 2 days with hail, the 4th saw ice pellets and the 11th a mixture of snow grains, snow pellets and a flurry of snow all during the evening from 1930 GMT. No thunder was heard in the month.
With a mean temperature of 10.5C (+0.4 on the 10-y average) it was the warmest since 1999 (10.5C) but ranked 7th in records since 1979. The years 1990 and 1997 each with 10.7C were warmer. The mean maximum 13.6C (+0.3) ranked only 8th with the minimum 7.4C (+0.5) ranking 4th. On the 30-y (1971 - 2000) average the mean minimum was +1.0C while the maximum was only +0.2C and the mean +0.6C. This reflects the kind of year it was with rather modest maximum temperatures but warmer minimums. The highest maximum of 24.7C (-3.0) on 16th May was even cooler than the 25.9C in 2001 and was 2nd lowest on record to the 24.0C on 28th August 1981. The number of warm days (20C, or more) numbered 28 (-9 on LTA). General cloudiness (77% at 09 GMT) at night helped to prevent cooling under clear skies and enhanced the minimum temperatures. Highest was 17.0C (0.0) on 17th May with the lowest -2.3C on 2 January (+1.9). Airfrosts numbered only 7, the lowest number on record at this station, and ranking 3rd in Anglesey since 1942. Only 1975 with 2 and 1988 with 6 had fewer. It was airfrost-free from 3rd March to 17th December. The number of ground frosts were 57, not unusually fewer ranking 24 on the Anglesey record, and frost-free from 5 May to 18th October. The mean soil temperature at 30 cm was 11.5C (+0.5) but not as warm as the 11.6C seen in 1999.
Rainfall at 1187.2 mm was 108% of average (111% of LTA ranking 18th wettest since 1928 and 116% of the 1971 - 2000 average). There were 5 months with more than 100 mm. Wettest was February with 187.7 mm, the others November 184.6 mm, October 163.9 mm, December 113.1 mm and July 110.2 mm. There were 213 (+4) rain days with 0.2 mm, or more, and 161 (+2) wet days with 1.0 mm, or more. Days with 5 mm, or more, numbered 78 (+3) and there were 109 (-1) dry days (trace not counted). The wettest day was on 1st August with 36.5 mm but the 10th February with 33.7 mm and 20th October with 33.2 mm were not far behind. The driest month was September with 23.0 mm and had 20 dry days, with March on 39.0 mm with 13 dry days in second place.
There were only 3 days (-5.5) when thunder was heard while there were 27 days (+0.2) when hail (all types) fell. There were 4 days when hail >= 5 mm was seen, the largest was up to 10 mm diameter fell on 22 February.
Complete weather diary for 2002.
Complete daily observations for 2002.
Llansadwrn (Anglesey): Monthly weather data for 2002.
(~ Based on the 1992-01 average)
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Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year
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Air temperatures (C)
Mean max 9.3 9.3 11.2 12.7 15.2 16.7 18.0 18.8 18.1 13.6 11.8 7.9 13.6
Mean min 4.2 4.1 4.3 5.3 8.3 10.3 11.4 12.2 10.8 7.4 6.7 4.0 7.4
Mean 6.8 6.7 7.8 9.0 11.8 13.5 14.7 15.5 14.5 10.5 9.3 6.0 10.5
Anomaly~ +1.5 +1.0 +0.8 +0.4 +0.1 -0.2 -0.9 -0.3 +0.8 -0.4 +1.4 +0.5 +0.4
High max 12.3 11.4 16.0 15.8 24.7 22.6 23.0 23.0 23.5 22.2 15.0 15.2 24.7
Date 12 11 29 19 16 1 15 17 12 1 2 23 16 May
Low max 4.0 6.5 6.7 8.5 10.6 13.3 14.2 14.2 14.9 8.9 8.5 2.6 2.6
Date 9 23 1 14 1 30 1 9 16,19 29 16 11 11 DEC
High min 9.2 8.5 8.4 10.2 17.0 13.8 16.6 15.7 14.0 12.3 9.9 10.3 17.0
Date 21 2 22 22 17 17 29 7 4 1 27 24 17 May
Low min -2.3 0.1 -0.7 1.0 2.9 7.3 8.3 8.8 7.2 2.0 3.2 -0.7 -2.3
Date 2 21 2 15 4 5 18 31 24 24 17 18 2 Jan
Grass min -7.3 -4.4 -2.7 -2.3 -0.8 4.0 5.2 4.8 3.2 -1.8 -1.8 -5.4 -7.3
Date 2 21 2 15 3 5 13,24 31 24 24 17 18 2 Jan
Atmospheric moisture means
RH (%) 86 88 86 82 82 84 85 91 84 89 88 90 86
Dew point (C) 4.2 4.5 5.2 5.9 8.7 10.5 12.3 14.0 11.7 8.1 6.8 3.9 8.0
Soil temperatures (C)
5 cm 5.0 5.8 6.3 9.2 12.9 15.4 16.8 16.6 14.6 9.9 7.8 4.8 10.4
10 cm 5.2 6.2 6.4 8.9 12.3 14.7 15.9 16.2 14.4 10.3 8.3 5.2 10.3
20 cm 5.5 6.8 7.2 9.5 12.7 15.0 16.2 16.8 15.2 11.4 9.0 5.9 10.9
30 cm 5.6 7.1 7.7 10.4 13.4 15.6 16.8 17.5 16.2 12.3 9.4 6.2 11.5
50 cm 6.1 7.5 7.9 10.5 13.2 15.3 16.4 17.3 16.4 13.1 10.0 7.1 11.7
100 cm 6.8 7.9 8.1 10.1 12.3 14.2 15.3 16.4 15.9 13.6 10.8 8.3 11.6
Rainfall (mm)
Rain tot 99.1 187.7 39.0 79.1 61.2 68.8 57.5 110.2 23.0 163.9 184.6 113.1 1187.2
Rain % ave~ 102 198 48 105 90 95 94 140 23 147 149 90 107
Days, dry 3 4 13 12 12 9 11 8 20 5 3 9 109
Days >=0.2 18 22 15 17 16 18 13 17 8 23 26 20 213
Days >=1.0 14 16 10 14 14 13 11 14 5 15 19 16 161
Days >=5.0 6 10 2 7 3 5 4 6 2 12 11 10 78
Max fall 17.8 33.7 8.6 15.5 13.5 16.7 13.8 36.5 12.0 33.2 25.5 22.8 36.5
Date 25 10 30 29 29 14 4 1 9 20 8 29 1 Aug
Evaporation
Piche (mls) 34.7 28.9 37.9 47.4 55.3 46.7 38.6 29.9 37.7 30.0 30.5 21.6 439.2
Lysimeter (mm) 8.1 11.9 23.2 30.6 50.3 61.1 47.8 36.9 27.3 6.9 4.9 -9.0 300.0
Weather (days)
Air frost 4 0 1 0 0 0 0 0 0 0 0 2 7
Ground fr 11 12 9 5 2 0 0 0 0 2 4 12 57
Sl/snow 0 3 1 0 0 0 0 0 0 0 0 1 5
Sn lying 0 0 0 0 0 0 0 0 0 0 0 0 0
Thunder 1 0 0 0 0 1 0 0 0 0 1 0 3
Hail <5 mm 3 6 3 2 1 0 0 1 1 3 1 2 23
Hail >=5 mm 0 1 0 0 0 0 0 0 0 2 1 0 4
Fog at 09h 0 0 0 0 0 0 0 0 0 0 0 0 0
Gales 9 8 1 1 3 1 0 0 0 1 0 1 25
Wind direction at 09h (days)
N 1 2 0 2 4 3 1 5 2 3 1 2 26
NE 0 0 4 5 5 0 4 4 7 2 0 8 39
E 1 0 4 2 2 1 0 1 3 4 1 11 30
SE 2 1 1 1 3 1 1 3 2 1 8 1 25
S 11 4 9 7 9 8 5 3 2 8 8 3 77
SW 7 10 9 5 5 9 11 6 3 2 4 3 74
W 4 6 3 4 2 5 2 0 4 3 3 1 37
NW 1 5 0 3 1 1 4 1 0 2 1 2 21
Calm 4 0 1 1 0 2 3 8 7 6 4 0 36
Autographic records of rainfall and frost duration (h)
Rain 86.8 134.9 45.0 73.0 70.2 61.2 56.7 80.1 17.0 115.4 127.6 114.3 982.2
Frost 22.9 0.0 3.8 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 11.1 37.8
Cloud cover at 09 GMT
Mean (%) 83 83 67 73 79 85 83 79 68 74 73 77 77
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These pages are designed and written by Donald Perkins © 2002Page dated 1 February 2002http://www.llansadwrn-wx.co.uk
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