Davis Vantage Vue AWS at Gorwel Heights in Llanfairfechan.

Llansadwrn (Anglesey) Weather:
Monthly and Annual
Summary for 2019

Logo: Llansadwrn Weather - Melin Llynnon, Ynys Môn




January 2019

Dull and relatively dry with temperatures a little above the averages

December 2018 and January exceptionally dull months

A mild beginning turning colder and wetter in the second half of the month

Another dull month with 34.8 h of sunshine recorded at RAF Valley (63%) & [60%] of averages, dullest since 2014 and ranked 7th dullest on the Anglesey record since 1930. The sunniest day was on the 30th having 6.4h and there were 11 sunless days. Dec 18 and Jan 19 total sunshine annomaly back to 1930 compared with 1981-2010 climatological average.Valley began recording sunshine in August 1946, records back to 1930 were those kept by the Holyhead Coastguard. Combining the months of December 2018 and January 2019 there were just 54.6h and this proved to be the dullest on record. The graphic shows the sunshine duration months prior to August 2005 are Kipp & Zonen corrected (see Monthly Report for 2005); the instrument was changed from the old Campbell-Stokes to a modern Kipp & Zonen electronic one. The graphic shows the differences from the 1981-2010 climatological mean value; Dec/Jan shows the greatest negative difference (anomaly). The early instrument was invented by John Francis Campbell in 1853 and modified in 1879 by Sir George Gabriel Stokes. The original design by Campbell consisted of a glass sphere set into a wooden bowl with the sun burning a trace on the bowl. Stokes's refinement was to make the housing out of metal and to have a card holder set behind the sphere.

In Llansadwrn the January mean global solar radiation was 2.56 MJ m -2. The brightest day was on the 30th with 5.67 MJ m -2 and the dullest 0.75 MJ m -2 on the 7th with three more days having 1 MJ m -2 , or less. The brightest hour was that beginning 12 GMT on the 30th with 306 W m -2. There was nine sunless days.

January was a relatively dry month with 70.3 mm of rainfall recorded in Llansadwrn (70%) & [69%] of averages, least since 2017 ranking 21 in Llansadwrn records back to 1928. The wettest day was on the 26th with 21.2 mm. There were 7 days without any precipitation and 9 dry days (those <0.2 mm). There were 22 rain days (those >=0.2 mm); 10 (-7.3) wet days (those >= 1.0 mm) and 5 days (-2.4) had 5 mm, or more. Rainfall at Gorwel Heights, Llanfairfechan tattled 65.2 mm [57%] of average. Here there were 12 dry days; 19 rain days; 10 wet days, and 5 had 5 mm, or more. Rainfall duration (wet hours) were 92 h in Llansadwrn and 76 h at Gorwel Heights.

Temperatures overall were a little above average. In Llansadwrn the monthly mean was 5.3C [(0.2)] of average, lowest since 2015. The mean maximum was 7.5C [(-0.1)] with the highest 11.3C (-0.8) on the 25th with the lowest 2.8C on the 31st. The mean minimum was 3.1C [(0.5)] with the highest 7.9C on the 7th and the lowest -2.4C on the 31st. There were 3 days that had air frost and in total there were 22.3 h of frost.

A Gorwel Heights the mean temperature was 5.9C [-0.3] of average, The highest maximum was 11.4C on the 6th and the lowest minimum -0.5C on the 31st the only day in the month with air frost duration 7.3h.

The second half of the month was colder and sleet and snow fell on 6 (+2.5) days with brief lying snow on 2 (+0.6) on the 22nd and 30th. Small hail (snow pellets and or ice pellets) fell on 8 (+1.3) days.

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February 2019

Warmest February on record at this station. Near average rainfall

Near normal temperatures at the beginning, record breaking well above average at the end

The mean temperature of 8.3C [(+3.0)] was the highest on record since before 1979. The mean maximum too was highest recorded here 11.6C (+3.5) & [+3.3] of averages with the highest maximum 19.5C on the 25th (+6.9). The previously highest February temperature of 17.2C on the 28th in 1985 was firstly beaten on the 22nd when 17.9C was recorded. The 18.9C on the 26th also exceeded this temperature for the third time. On 16 days the 10C threshold was exceeded, and on 7 days 15C was exceeded. A truely remarkable month.

Rainfall was 78.2 mm, highest since 2017 (103%) & [98%] of averages.

 

Winter 2018/19

It was the warmest winter recorded at this station since records began in 1979, with a mean tempersture of 7.1C narrowly beating the 7.0C recorded in 2016 and 6.9C in 1998.

Winter seasonal averages Anomalies
10-y 30-y
Temperature (C)
Mean maximum 9.7 +1.6 +1.8
Mean minimum 4.5 +1.5 +1.9
Mean 7.1 +1.6 +1.9
Rainfall (mm) 295.7 88% 98 %

 

 

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March 2019

Very wet with above average temperatures and below average sunshine

Wet and wintry in the first half of the month, dry and brighter at the end.

Rainfall of 174.1 mm was the second largest March rainfall in Llansadwrn since before 1928, (248%) & [204%] of averages. Largest since 1981 that had 205.9 mm. The wettest day was on the 11th with 27.2 mm and the 15th had 25.7 mm. Nine days (+0.6) in the second-half of the month had no precipitation and there were 11 (-3.5) dry days. Rain days numbered 20 (+3.5); wet days 19 (+6.2); and significantly days with 5 mm, or more, 11 (+5.4). Rainfall in Llanfairfechan, Gorwel Heights, totalled 191.8 mm [222%] of average. Here the wettest day was on the 15th with 36.4 mm, but the 11th had 28.4 mm a little more than Llansadwrn. Dry days numbered 13; raindays 18; wet days 17; and days with 5 mm, or more, 11. Rainfall duration (wet hours) in Llansadwrn were 161 averaging 1.1 mm/h, while Gorwel had 134 hours averaging 1.4 mm/h.

The mean temperature in Llansadwrn was 7.8C (+1.0) & [+0.8] of averages, highest since 2017, and ranking 11 in records since 1979. The mean maximum was 10.9C and the highest maximum 14.1C (-2.0) on the 21st, the lowest was 7.1C (+2.6) on the 7th. The mean minimum was 4.6C with the 8th having the lowest recorded 1.6C (+1.9). The mean grass minimum was 1.6C (+1.9) and the lowest was -3.6C (+1.4) on the 24th. There were 10 ground frosts (-4.8). The mean temperature at Gorwel Heights was 8.2C (+0.8). The highest maximum was 17.3C on the 20th and the lowest 6.9C on the 7th. The lowest minimum recorded was 1.7C on the 10th.

March was rather dull with Valley recording 103.5h (77%) & [91%] of averages, lowest since 2016 ranking 25th lowest on the Anglesey record. The sunniest day was on the 25th with 9.1 h. There were 8 sunless days, significantly more than Llansadwrn which had only 3.

In Llansadwrn the mean solar radiation was 8.3 MJ m -2 with the most 17.15 MJ m -2 received on the 29th and the least 1.15 MJ m -2 on he 16th. The brightest hour was on the 29th from 12 noon having 665 W m -2. The brightest hour on the dullest day on the 16th had only 37 W m -2 in the hour from noon.

The beginning of the month was a little wintry at times with a slight snow and snow pellet shower on the 10th; ice pellets on the 4th and 17th; and small unidentified small hail on the 16th. Thunder was hear on the 5th and 17th.

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April 2019

Temperature above average, but rather wet with sunshine below average

Mostly dry in the middle of the month becoming warm before turning colder

There was a warm spell of weather beginning the second half of the month with a spell of 6 consecutive days 20C, or more. The highest maximum was 24.4C on the 19th and was the second highest at this station in April being only beaten by the 25.3C on 16th in 2003. The mean maximum was 10.3C (+1.0) & [+1.3] of averages, highest since 2014 ranking 6th. The mean minimum 6.2C (+0.8) & [+1.3] of averages, highest since 2014 and ranking 4th. The lowest minimum was 1.5C on the 4th while the lowest grass minimum was -2.5C on the 14th. There were 7 ground frosts (-0.7). The mean temperature was 10.2C (+1.0) & [+1.3] of averahes, highest since 2014. At Gorwel Heights the highest maximum was 23.8C on the 19th and the lowest minimum 1.9C was on the 4th. The mean temperature was 10.6C [+1.6] of average.

There were 17 dry days (+3.0) and mostly in the middle of the month. There were two spells with no precipitation of nine days 6-14th and seven days 17-23rd inclusive. Rain occurred at the beginning with 12.6 mm falling on the 1st, and then towards the end of the month with 14.8 mm falling on the 26th this the largest daily fall. Rain days were 13 (-3.0); wet days 11 (+0.1); and significantly 8 days (+2.4) of 5 mm, or more. Total rainfall was 77.5 mm (155%) & [122%] of averages. Gorwel Heights was wetter with 86.2 mm [137%] of average. Here there were 18 dry days; 12 rain days; and 10 wet days. There were 7 days with 5 mm, or more.

Sunshine at RAF Valley was 138.8h (76%) & [88%], lowest since 2018 and ranking 22 on the Anglesey record. The sunniest days was on the 21st with 12.9h of sunshine, there were 5 sunless days. Solar radiation measured in Llansadwrn averaged 13.23 MJ m -2 with 5 days having 20 MJ m -2 , or more. The most was 20.82 MJ m -2 on the 21st and the dullest 4.64 MJ m -2 on the 27th. The brightest hour was on the 13th having 740 W from 12 noon. The hour from 14 to 15 GMT on the on the 24th was particularly dull with only 45 W m -2, there was a heavy shower of rain that fell at a rate of up to 17 mm/h at 1606 GMT. The 24th had dry deposition of Saharan dust overnight and more dust was washed out in rain rain commencing at 14 GMT.

 

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May 2019

A dry month and with its ups and downs average temperatures

A cool beginning a very dry warmer middle and wetter end

May was a fairly dry month with only 39.1 mm of rain (53%) & [63%] of averages, lowest since 2010 ranking 21 since 1928. The first half of the month was driest with just 9.4 mm (13%) & [15%] of the monthly total averages, the second half wetter with 29.7 mm. The wettest day was on the 29th with 13.4 mm. There were 10 days (-1.8) with no precipitation and 14 dry days (-1.1). Rain days were 17 (+1.1); wet days 6 (-5.9); and days with 5 mm, or more, 3 (-1.7). By the 25th soil moisture content under grass had reduced to 31.3% dry mass. On the met plot having bare soil it had fallen to 10.5% below the permanent wilting percentage of 15% for the local soil. Llanfairfechan, had much more rain with 67.2 mm [111%] at Gorwel Heights and 53.8 mm at Gorddinog. The wettest day at Gorwel Heights was 14.4 mm on the 7th. Dry days were 13; rain days 18; wet days 14; and days there were 7 days with 5 mm, or more.

Temperatures were lowest at the beginning of the month with 2 touches of ground frosts recorded on the 5th (-0.4C) and 12th (-0.1). The mean temperature for the first 15 days of the month was 10.1C (-1.5) & [-1.6] of averages. The second half of the month was warmer and resulted in a monthly mean 11.5C close to the averages (0.0) & [-0.2]. The highest maximum was 21.7C (-0.8) recorded on the 14th and the lowest maximum was 8.7C (-2.1) on the 8th. The lowest minimum was 3.0C (-0.8) on the nights of the 4th and 5th. At Gorwel Heights the mean temperature was 11.7C (+0.2) with the highest maximum 21.3C on the 14th and 30th. The lowest minimum was 2.5C on the 4th.

Sunshine was less than the decadal average (95%), but above the 30-y average [105%] of averages. The sunniest day at Valley was on the 11th with 14.1h and there were 3 sunless days.

Spring 2019

Despite it being a dry May the Spring rainfall 290.7 mm was the largest since 2006 and the 6th wettest in Llansadwrn since 1928. Overall it was a little warmer than average with the mean 9.9C [(+0.7)], lowest since 2017, but ranking 15th in station records since 1979.

Spring seasonal averages Anomalies
10-y 30-y
Temperature (C)
Mean maximum 13.5 +0.8 +0.5
Mean minimum 6.2 +0.6 +0.8
Mean 9.9 +0.7 +0.7
Rainfall (mm) 290.7 150% 135%

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June 2019

Wet. Near average temperatures, but 30.6C the highest June maximum and seventh highest on record since 1979 at the station

Cool and wet at the beginning, drier and hot for one day at the end

An unusual month with the mean temperature of the first 15-days 12.0C (-2.3) & [-1.9] of averages and most noticeable the low maxima with a mean 14.8C [(-3.0)]; also wet the 71.6 mm (86%) and [106%] of the month's average.

The final monthly temperature mean was 14.0C lowest since 2015 (-0.3) & [0.1] of averages. The mean maximum turned out to be 17.5C (-0.4) and [-0.3] despite the highest June maximum at this station of 30.6C on the 28th. This was the earliest 30C in the year to be recorded here and only the seventh since records began in 1979. The highest minimum was 15.6C(+0.8) on the 28th this only ranked 11 in my records. The lowest minimum was 6.6C (+0.1) on the 10th, but the lowest grass minimum of 3.4C was on the 6th.

Gorwel Heights had a maximum of 29.3C on the 28th with a low relative humidity value of 26%; Gorddinog had a maximum of 30.0C.

Rainfall was 100.1 mm (136%) & [148%] of averages, highest since 2017, ranking 21 in Llansadwrn records since 1929. The largest falls were 22.2 mm on the 7th and 16.0 mm on the 23rd. There were 10 days (-3.0) without any precipitation and 11 (-5.5) dry days. Rain days totalled 19 (+5.5); wet days 12 (+1.5); and days with 5 mm, or more, were 6 (+1.5). Llanfairfechan was wetter with Gorwel Heights receiving 137.6 mm [210%] while Gorddinog had 128.1 mm. Number of wet hours at Gorwel were 104 with an average rate of fall of 1.3 mm per hour while at Llansadwrn there were 118 wet hours and 0.8 mm per hour.

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July 2019

A warm month with above average temperatures and two hot days, rain below decadal average

Very dry at the beginning of the month, with some wet days at the end

A warm month with 15 days having a maximum of 20C, or more, and 2 hot days 25C, or more. The mean maximum was 16.7C [(+1.0)] of averages, lowest since 2017, but ranking 8th highest since 1979. The mean maximum was 20.4C (+1.2) & [+0.9] of averages, the highest maximum was 29.6C (+3.5) of the decadal average on the 25th; the 24th had 25.2C. The highest maximum at Gorwel Heights was 27.1C on the 23rd. The mean minimum 13.1C (+0.7) & [+1.1] of averages, was lowest since 2017 but 6th highest in station records. The highest minimum was 18.3C on the 26th (+1.8); 18.9C at Gorwel Heights on the 26th . The lowest minimum was 8.2C (-0.7) and the lowest grass minimum 5.0C both on the 7th.

Rainfall in Llansadwrn was 76.1 mm (81%) & [109%] of averages largest since 2017 ranking 44 since 1928. The wettest days were on the 30th with 21.4 mm and the 21st with 17.6 mm. There were 15 dry days (+2.6), dry days being defined as those having <0.2 mm, and 9 (-0.50) received no precipitation. Rain days were 16 (-2.6); wet days 9 (-5.6); and days with 5 mm, or more 5 (-1.5).

Rainfall at Gorwel Heights was 84.4 mm [144%]. The wettest day was on the 30th having 32.0 mm while 16.4 mm fell on the 19th.

The surface soil under grass at the beginning of the month was very dry with a soil moisture content of 36.7% dry mass. After wet days at the end of the month this had risen only a little to 37.3% dry mass. Undisturbed surface soil on the bare met plot had a moisture content at the beginning of the month of 11.4% dm and 12.9% dm at the end of the month, below the permanent wilting percentage of 15% dm.

Sunshine at RAF Valley was 181.5 h (provisional), lowest since 2016, ranking 23rd highest on the Anglesey record since 1931. The sunniest day was on the 3rd with 14.6h, there were 3 sunless days.

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August 2019

Above average temperatures while rainfall was close to the averages

The first half was wetter than usual and the second half had one hot day

Rainfall in Llansadwrn was 90.2 mm, most since 2017 and (96%) & [104%] of averages. Gorwel heights had 93.8 mm this wetter than average [111%]. The wettest days were on the 16th in Llansadwrn with 19.0 mm; Gorwel Height's wettest day was on the 10th with 23.2 mm while the 9th had 15.6 mm. Wet hour duration was similar at both stations 105 and 103 respectively. In Llansadwrn there were 6 (-1.5) days with no precipitation; dry days were 11 (-1.2); rain days 20 (+1.2); and wet days 16 (+2.6). Falls of 5 mm, or more, were 5 in llansadwrn and 6 at Gorwel heights.

The mean temperature in Llansadwrn was 16.3C (+1.2) & [+0.7] of averages, highest since 2004 ranking 8th highest in station records since 1979. The meamn maximum was 19.4C with the highest 26.1C, the only hot day' on the 24th. Days with 20C, or more, totalled 11 in Llansadwrn and 13 at Gorwel Heights.

 

Summer 2019

Above average temperatures and rainfall.

 

Summer seasonal averages Anomalies
10-y 30-y
Temperature (C)
Mean maximum 19.1 0.7 0.3
Mean minimum 12.2 0.5 0.9
Mean 15.7 0.6 0.6
Rainfall (mm) 266.4
102%
119%

 

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September 2019

Very wet, temperatures and sunshine above average

A short warm and dry spell beginning the second half with some wet days throughout

Rainfall was 146.7 mm (148%) & [153%] of averages, largest in September since 2012 ranking one of the 17 wettest in Llansadwrn since 1928. The wettest day was on the 30th having 24.2 mm. Rainfall at Gorwel Heights on the same day was 17.2 mm. Ten days had 5 mm, or more, that 3.9 days above average. There were 8 (-0.6) days with no precipitation and 9 (+0.4) dry days. Rain days numbered 21 (+3.6) and wet days 16 (+3.9). Currently total rainfall for the year 852.3 mm is just 4.5 mm below that accumulated in Llansadwrn's wettest year in 2000.

Rainfall at Gorwel Heights was 133.6 mm [137%] of average. The wettest day was on the 15th with 20.0 mm. There were 21 rain days and 17 wet days. Rainfall at Gorddinog was 124.5 mm with 18.6 mm on the 15th. Rainfall in Llansadwrn on the 15th was 17.4 mm.

Temperatures were above the average. The mean 14.2C (+0.5) & [+0.4] this due to a warm spell beginning the second half of the month. There was one hot day on the 21st when the temperature reached 26.2C (+4.5).

The mean temperature at Gorwel Heights was 14.6C [+0.1]. The month's maximum was 24.7C on the 21st, but 26.4C was reached at Gorddinog on the same day.

Sunshine at RAF Valley was a provisional 140.7h, most in September since 2015, with the sunniest day 11.6h on the 19th. There were 2 sunless days. It was much cloudier in Llansadwrn where there were 6 sunless days.

 

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October 2019

A wet month and cool with temperatures a little below averages, fairly sunny at times.

Changable throughout

A wet October with rainfall of 165.0 mm )150% & [125%] of averages most since 2014 and the 14th in Llansadwrn records back to 1928. The wettest day was on the 25th when it rained all day. The wet hour duration was 23. Other wet days were on the 3rd 18.6 mm (13 hours duration); the 10th 13.5 mm (14 hours); the 13th 11.4 mm (7 hours); the 17th 15.4 mm (10 hours); the 18th 21.4 mm (19 hours). In all the number of wet hours were 156. We did have 7 days (-0.6) without any precipitation and there were 8 dry days (-3.4) having <0.2 mm. Rain days numbered 23 (+3.4); wet days 19 (+5.0); and there were 10 days (+3.0) that had 10 mm, or more. Llanfairfechan was equally as wet with 161.2 mm of rain [128%] of average falling over 144 wet hours, the rate of rainfall at both stations was 1.1 mm/h.

The mean temperature was 10.5C (-0.9) & [-0.3] of averages, lowest since 2012. Maximum temperatures were below average, the mean maximum 13.1C (-1.0) & [ -0.9] and significantly the highest maximum 16.8C on the 15th well below the norm (-3.4). The lowest minimum 3.3C on the 26th was (-0.6) and the lowest grass minimum -1.0C on the 27th, one of two ground frosts, (-0.6) of average. Llanfairfechan with its microclimate did not fare much better with a mean temperature of 11.0C; the highest maximum on the 7th was 18.1C.

Sunshine at RAF Valley a provisional 95.7 h with 4 sunless days. The sunniest day was on the 29th having 9.9h. Again cloudier in Llansadwrn where there were 8 sunless days. Here the brightest day was on the 12t with 10.09 MJ m -2; the dullest day was on the 25th with 0.97 MJ m -2; while the brightest hour was 517 W m -2 in the hour 11 and 12 GMT.

 

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November 2019

A cool, but dry month. It was wetter in Llanfairfechan.

Wettest at the beginning, drier and cooler in the middle with a colder dry ending

Temperatures were consistently below average. The mean 7.1C (-2.0) & [-0.6] was lowest since 2016, and ranked ninth lowest in the past 40-years. The mean maximum (-3.4) & [-1.1] the highest 13.7C (-1.4) on the first and the lowest 6.6C (+0.3) on the 14th. The mean minimum 4.9C (-0.6) & [-0.1] was closest to the averages. The lowest -0.4C on the 9th was the only air frost. There were 8 ground frosts (+0.2) with the lowest -4.4C on the 8th (-1.2). The mean temperature at Gorwel Heights was 7.4C [-1.4], with the mean maximum 9.4C (highest 16.7C on the 1st) and mean minimum 5.6C (lowest 2.0C on the 9th).

Rainfall in Llansadwrn was 105.6 mm (74%) & [84%] of averages, lowest since 2014 ranking 33 since 1928. The wettest days were on the 1st with 17.2 mm, and on the 10th with 16.5 mm, the only two in double digits. There were 3 days (-0.6) with no precipitation and 7 dry days (-0.3). There were 23 (+0.3) rain days; 19 (+1.4) wet days; and 9 (+0.3) days having 5 mm, or more. It was a bit wetter at Gorwel heights where 127.0 mm fell [94%] of average. There were 6 dry days; 23 rain days; 23 wet days; and 10 had 5 mm, or more. There were 3 days with 10 mm, or more. The most fell on the 16th 13.6 mm; followed by 12.6 mm on the 7th and 10.6 mm on the 26th. The greater rainfall at Gorwel was reflected in the number of wet hours duration 156h compared with the 132h in Llansadwrn.

 

Autumn 2019

A wetter than average autumn the 417.3 mm [(119%)].

Temperatures were consistently below average

Autumn seasonal averages Anomalies
10-y 30-y
Temperature (C)
Mean maximum 13.3 -1.2 -0.6
Mean minimum 7.9 -0.5 -0.2
Mean 10.6 -0.8 -0.2
Rainfall (mm) 417.3 119% 119%

Monthly data 2019

Llansadwrn (Anglesey): Monthly weather data summary for 2019
Anomaly ~ is based on the 2009-18 average.
Anomaly 30-y is based on the 1981-2010 average.
.
.
Air temperatures (C) Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year
.
Mean max 7.5 11.6 10.9 14.3 15.4 17.5 20.4 19.4 17.5 13.1 9.3 14.3
Mean min 3.1 4.9 4.6 6.2 7.7 10.5 13.1 13.1 10.8 7.9 4.9 7.9
Mean 5.3 8.3 7.8 10.2 11.5 14.0 16.7 16.3 14.2 10.5 7.1 11.1
Anomaly~ 0.2 3.0 1.0 1.0 0.0 -0.3 1.0 1.2 0.5 -0.9 -2.0 0.2
Anomaly 30-y 0.2 3.0 0.8 1.3 -0.2 0.1 1.0 0.7 0.4 -0.3 -0.6 0.4
High max 11.3 19.5 14.1 24.4 21.7 30.6 29.6 26.1 26.2 16.8 13.7 30.6
Date 25 25 21 19 14 28 25 24 21 15 1 .
Low max 2.8 5.1 7.1 6.3 8.7 11.4 17.2 16.2 13.9 8.5 6.6 2.8
Date 31 2 7 3 8 12 11 10 15 26 14 .
High min 7.9 12.3 8.4 12.5 12.8 15.6 18.3 16.1 16.8 12.1 9.4 18.3
Date 7 23 21, 22 20 31 28 26 9 22 1 1 .
Low min -2.4 -0.9 1.6 1.5 3.0 6.6 8.2 8.4 7.3 3.3 -0.4 -2.4
Date 31 3 8 4 4, 5 10 7 12 18 27 9 .
Grass min -6.5 -5.7 -3.6 -2.5 -0.4 3.4 5.0 5.0 4.7 -1.0 -4.4 -6.5
Date 31 3 24 14 5 6 7 13 30 27 9 .
.
MSL Pressure at 09 GMT (mb) 1019 1017 1015 1013 1017 1014 1016 1012 1016 1010 1001 1014
Highest 1045.4 1035 1038 1032 1040 1030 1030 1024 1038 1028 1028 1045
Date 2 25 28 20 13 26 3 21 13 29 30 .
Lowest 983.8 984.0 976.6 987.8 989.4 999 999 988 988.9 991 973 973.0
Date 31 8 6 24 8 5 20 10 29 18 2 .
.
Means at 0900 GMT .
Air temperature (C) 4.8 7.5 7.4 10.6 12.0 14.2 16.8 16.3 13.9 9.8 6.7 10.9
Dew point (C) 3.4 4.9 5.4 5.8 8.3 10.8 13.8 13.6 11.9 8.0 5.1 8.3
RH% 91 85 88 73 79 81 83 85 88 89 9.3 77
Soil temperatures (C) .
.
5 cm 4.7 5.4 7.0 9.9 13.5 15.8 18.1 16.9 14.2 10.0 6.5 11.1
10 cm 5.1 5.7 7.1 9.4 12.7 15.5 17.3 16.5 14.8 10.4 7.0 11.0
20 cm 5.3 5.7 7.6 10.4 13.1 15.8 17.5 17.3 15.3 11.3 7.4 11.5
30 cm 6.3 6.4 8.3 10.8 13.2 15.3 17.6 17.6 15.5 12.0 8.2 11.9
Anomaly~ 1.1 1.2 1.3 0.7 0.2 -0.7 0.3 0.6 0.3 -0.6 -1.0 0.7
50 cm 7.2 6.8 8.6 10.8 13.0 15.5 17.3 17.5 15.9 12.7 9 12.2
100 cm 8.2 7.4 8.8 10.5 12.3 14.1 16.1 16.6 15.7 13.5 10.2 12.1
Anomaly~ 1.1 0.7 1.2 0.7 0.4 -0.4 0.3 0.5 0.4 -0.1 -0.9 0.6
.
Rainfall (mm) .
.
Rain tot 70.3 78.2 174.1 77.5 39.1 100.1 76.1 90.2 146.7 165.0 105.6 1122.9
Rain % ave~ 70 103 248 155 53 136 81 96 148 150 74 98
Rain % 30-y 69 99 204 122 63 148 109 104 153 128 84 103
Days 0.0 7 5 9 17 10 10 9 6 8 7 3 91
Days <0.2 9 9 11 17 14 11 15 11 9 8 7 121
Days >=0.2 22 19 20 13 17 19 16 20 21 23 23 213
Days >=1.0 10 12 19 11 6 12 9 16 16 19 19 149
Days >=5.0 5 5 11 8 3 6 5 5 10 10 9 77
Max fall 21.2 19.4 27.2 14.8 13.4 22.2 21.4 19.0 24.2 34.8 17.2 34.8
Date 26 6 11 26 29 7 30 16 30 25 1 .
Highest rate (mm/h) 32 23 48 37 37 19 81 56 75 101 37 101
Date 21 6 18 26 25 16 30 5 26 10 10 .
Average rain per hour (mm) 0.8 0.8 1.1 0.8 0.6 0.8 1.1 0.9 1.2 1.1 0.8 0.9
.
Evaporation .
.
Piche (mls/ mm) 18.4 47.6 28.0 53.0 43.1 50.0 43.3 49.8 37.1 31.0 22.1 423.4
Lysimeter PE (mm) 13.4 33.2 42.2 74.5 77.4 100.0 98.5 62.8 61.8 36.7 28.9 629.4
AWS ET calculated 11.3 31.3 38.1 55.2 69.0 72.8 70 64.7 41.7 27.8 14.3 496.2
.
Weather (days) .
.
Air frost 3 2 0 0 0 0 0 0 0 0 1 6
Ground fr 15 10 10 7 2 0 0 0 0 0 8 52
Sl/snow 6 2 1 1 0 0 0 0 0 0 0 10
Sn lying 2 0 0 0 0 0 0 0 0 0 0 2
Thunder 0 0 2 1 0 0 2 0 0 1 0 6
Hail <5 mm 8 3 4 2 4 1 0 0 0 1 3 26
Hail >=5 mm 0 0 0 1 0 0 0 0 0 0 0 1
Fog at 09h 0 0 0 0 0 0 0 0 0 0 0 0
Gales in SE Anglesey 2 1 1 2 0 1 0 0 0 0 0 7
.
Wind direction at 09h (days) .
.
N 5 3 1 1 7 1 2 3 4 3 9 39
NE 2 1 1 3 4 7 3 0 2 2 2 27
E 0 0 1 8 1 1 2 0 0 3 4 20
SE 3 4 0 10 1 3 1 2 1 3 7 35
S 1 5 6 1 6 2 10 6 2 7 4 50
SW 7 11 11 3 8 13 7 13 13 7 1 94
W 5 2 11 2 2 3 4 7 5 4 2 47
NW 6 2 0 2 2 0 2 0 0 1 0 15
Calm 2 0 0 0 0 0 0 0 3 1 1 7
.
Wind speed mph .
.
Daily mean 3.8 8.0 7.3 2.8 3.0 4.2 3.5 5.3 4.4 4.3 4.2 4.6
Highest daily mean 11.2 19.0 15.5 8.8 9.8 9.9 11.1 12.1 10.5 11.4 14.3 19.0
Date 26 8 16 26 31 2 22 10 26 10 14 .
Mean gust 19.6 25.4 25.5 13.8 12.6 16.5 14.6 19.4 18.2 17.2 17.6 18.2
Highest gust 38 44 48 31 31 42 31 33 30 32 30 48
Date 26 8 16 26 31 2 22 29 11, 12 3 1 .
.
AWS records of rainfall and frost .
.
Wet hours (with 0.2 mm,or more) 92 98 161 99 66 118 68 105 124 156 132 1219
Frost duration (h) 26.5 7.8 0 0 0 0 0 0 0 0 1.7 36.0
.
Cloud cover at 09h. Mean % 79 74 78 74 79 79 77 78 76 71 79 77
.
Global solar radiation (MJ m-2) .
.
Llansadwrn
Sol rad mean 2.56 6.71 8.35 13.23 17.05 17.34 15.14 13.43 8.78 5.66 3.08 10.12
Maximum 5.67 13.62 17.15 20.82 29.70 29.59 27.57 25.13 14.68 10.09 6.30 29.70
Date 30 26 29 21 21 3 3 2 1 12 8 .
Minimum 0.75 2.02 1.15 4.64 6.87 5.13 4.11 4.04 2.83 0.97 1.19 0.75
Date 7 5 16 27 8 12 28 10 12 25 23 .
Brightest hour W/sq m 306 492 665 740 894 931 853 774 637 517 331 931
during hour beginning GMT 12 12 12 12 12 12 12 12 11 11 11 12
on day 30 26 29 13 21 17 3 2 7 2 8 .
Sunless days 9 4 3 5 3 5 4 6 6 8 12 65
.
Sunshine (h) .
[ ~ one or two missing days are derived] ~ ~ ~ ~ ~
Valley 34.8 110.2 103.5 138.8 204.4 204.6 181.5 179.0 140.7 95.7 48.9 1442.1
Average %~ 63 144 77 76 95 92 91 108 105 108 78 92
Average 30-y 60 138 91 88 105 119 109 111 110 98 85 101
Sunniest 6.4 10.1 9.1 12.9 14.1 15.7 14.6 12.7 11.6 8.9 8.1 15.7
Date 30 26 25 21 11 27 3 2 19 29 8 .
Sunless days 11 7 8 5 3 5 3 4 2 4 11 63
.
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year

Llanfairfechan, Gorwel Heights observations

Gorwel Heights (73 m), Llanfairfechan (Conwy): Monthly weather data summary 2019
# Anomalies based on 1981-2010 MetO Llanfairfechan DataPoint
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year
Air temperatures (C)
.
Mean max 7.6 12.0 11.1 14.1 15.1 17.9 20.4 20.0 17.4 13.3 9.2 14.4
Mean min 4.2 5.5 5.3 7.1 8.4 11.2 13.8 13.9 11.7 8.7 5.6 8.7
Mean 5.9 8.8 8.2 10.6 11.8 14.6 17.1 16.9 14.6 11.0 7.4 11.5
Anomaly [1981-2010] # -0.3 2.9 0.8 1.6 0.2 0.3 1.0 0.8 0.2 -0.6 -1.4 0.9
.
High max 11.4 19.3 17.3 23.8 21.3 29.3 27.1 24.9 24.7 18.1 16.7 29.3
Date 6 22 20 19 14, 15, 30 28 23 24 21 7 1 .
Low max 2.2 4.1 6.9 5.6 8.4 11.4 16.1 15.2 13.1 7.4 6.4 2.2
Date 31 1 7 3 8 12 31 11 15 26 9 .
High min 8.8 12.2 9.1 13.7 13.7 16.8 18.9 17.3 18.2 12.2 8.7 18.9
Date 7 23 21 20 26 28 26 3 22 8 25 .
Low min -0.5 -0.7 1.7 1.9 2.5 7.6 9.9 9.8 8.8 4.3 2.0 -0.7
Date 31 1 10 4 4 6, 14 7 12 8 27 9 .
.
MSL Pressure at 09 GMT (mb) 1019.4 1017 1015.2 1014 1018 1014 1016 1011 1016 1009.7 1001 1014
.
Highest 1045.9 1037 1037 1032 1040 1029 1030 1024 1037 1029 1029 1046
Date 2 25 28 20 13 26 3 21 13 29 30 .
Lowest 984 984 976 988 990 999 999 988 989 991 973 973
Date 31 8 6 24 8 5 20 10 29 18 2 .
.
Means at 0900 GMT
Air temperature (C) 5.7 8.5 7.9 10.4 11.7 15.0 17.3 16.9 14.8 10.6 7.1 9.5
Dew point (C) .3.3 4.6 5.3 5.7 8.3 10.3 13.4 13.5 11.1 7.4 4.4 43.7
RH% 85 78 84 74 80 75 78 80 79 81 83 80
.
Rainfall (mm)
.
Total 65.2 50.0 191.8 86.2 67.2 137.6 84.4 93.8 133.6 161.2 127.0 1198.0
% [1981-2010] # 57 64 222 137 111 210 144 111 137 128 94 109
.
Max fall 16.8 17.0 36.4 18.6 14.4 41.0 32.0 23.2 20.0 51.6 13.6 51.6
Date 26 5 15 26 7 7 30 10 15 25 16 .
Highest rate (mm/h) 65 18 38 12 58 97 75 116 104 57 34 116
Date 26 9 11 1 2 7 30 30 26 19 7 .
.
Wet hours (with 0.2 mm, or more) 76 58 134 96 67 104 63 103 122 144 156 1123
Average rain per hour (mm) 0.9 0.9 1.4 0.9 1.0 1.3 1.3 0.9 1.1 1.1 0.8 1.1
.
Days <0.2 12 15 13 18 13 15 18 10 9 8 6 137
Rain >=0.2 19 13 18 12 18 15 13 21 21 23 24 197
Wet >=1.0 10 10 17 10 14 11 10 16 17 14 23 152
Days >=5.0 5 3 11 7 7 5 6 6 9 9 10 78
.
Weather (days) .
.
Air frost 1 1 0 0 0 0 0 0 0 0 0 2
Frost duration (h) 7.3 5.3 0 0 0 0 0 0 0 0 0 13
Wind direction at 09h (days) .
.
N 2 1 2 4 10 6 3 4 2 2 3 39
NE 0 2 0 3 2 2 1 1 1 1 3 16
E 1 1 0 7 2 2 1 2 1 4 7 28
SE 6 2 2 8 2 2 1 1 3 4 8 39
S 5 10 7 1 2 5 6 8 7 7 4 62
SW 8 3 11 1 4 8 5 8 6 6 3 63
W 2 3 5 1 1 2 5 0 1 1 0 21
NW 2 1 1 3 2 1 4 0 2 1 0 17
Calm 5 5 3 2 6 2 5 6 7 5 2 48
.
Mean mph 3.2 5.6 4.4 5 2.1 3.5 1.8 2.9 2.8 3.4 4.9 3.6
Highest daily mean mph 8.0 15.1 10.3 17.2 6.2 13.1 5.4 6.6 14.8 8.3 19.9 19.9
Date 21 17 16 15 16 27 21 16 21 31 20 .
Mean gust 18.4 25.0 10.1 10.4 13.5 19.1 14.4 18.1 19.0 20.2 22.3 17.3
Highest gust 34 45 45 26 31 41 34 35 40 41 41 45
Date 26 8, 17 2, 16 15 30 27 21 31 21 30 20 .
.
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year

Acknowledgements

The Met Office at RAF Valley kindly supplied observational data from 1942 to 2011. Current data (provisional) are gathered from SYNOP reports and METAR, a few missing days sunshine observations this year were derived from nearby stations to complete the record. I am grateful Ivor McLean former Met Officer at RAF Valley for early Holyhead sunshine and various other observations; David Lee for use of his observations from Gorddinog; and Gordon Perkins (BlueTractorSoftware) for observations at Gorwel Heights and help with additional observations.


References

1: Prior J. (2006). Sunshine measurement. Weather 61, p. 77.

2: Kerr A. & Tabony R. (2004). Comparison of sunshine recorded by Campbell-Stokes and automatic sensors. Weather, 59 (4), pp. 90-95.



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