Davis Vantage Vue AWS at Gorwel Heights in Llanfairfechan.

Llansadwrn (Anglesey) Weather:
Monthly and Annual
Summary for 2017

Logo: Llansadwrn Weather - Melin Llynnon, Ynys Môn




January 2017

Another 'dry' winter month with temperatures generally above average

Alternating spells of colder and warmer weather

Rainfall of 48.0 mm (42%) & [47%] of averages, was least since 1997, ranking 11th in records back to 1928. The wettest day in terms of volume was on the 8th with just 9.2 mm. This fell over 5 hours duration, but on the 6th there were 14 h when it rained and only 7.2 mm was collected. Another damp day was on the 14th when 6.2 mm fell over 10 h duration. Four days had no precipitation what so ever. (-0.8) of average. Dry days that allow for <0.2 mm of rain, and may include other precipitation including dew, were 12 (+3.3) of average. Rain days(>=0.2 mm) numbered 19 (-3.3); wet days (>=1.0 mm) were 12 (-6.1); and days having 5 mm, or more, were 4 (-4.4). All categories were below average except dry days. At Gorwel Heights it was a little drier with 38.6 mm falling [34%] of average. Dry days were 10; rain days 21; wet days 10; and only 2 had 5 mm, or more.

Temperatures were above average for most of the month. The mean 5.7C was lowest since 2015, but was (+0.4) & [+0.6] of averages and ranked 13th warmest of the last 38-years. The highest maximum on the 30th was 12.7C (+0.2) & [+0.5] and the lowest 3.7C on the 12th was (+0.7). The lowest minima were in air 3.3C (+0.5) & [+0.7] on the 12th and on the grass -6.5C (-0.2) was recorded on the 5th and 26th. Earth temperatures were at 30 cm 6.1C (+0.7) and 100 cm 7.7C (+0.5). At Gorwel Heights the mean temperature was 6.8C [+0.5]; the highest maximum 15.1C on the 31st and lowest minimum 0.6C on the 22nd.

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February 2017

Fairly mild, windy and dull - temperatures and rainfall above averages

Wettest at the end of the month

A mild month generally with the mean temperature 6.5C (+0.9) & [+1.2] of averages, highest since 2011, ranking 7th highest in station records. The mean minimum showing the greatest anomalies was 4.1C (+1.5) & [+1.9] of averages, again highest since 2011 and ranking 4th. The highest minimum was 8.3C on the 18th while the lowest -0.3C and the only air frost was for only 2 hours duration. The mean maximum showing the smallest anomaly was 8.9C (+0.4) & [+0.6] of averages with the highest 14.3C on the 2nd and lowest 4.2C on the 10th. There were 12 ground frosts (-3.7) the lowest recorded was -5.6C on the 9th. At Gorwel Heights the mean temperature was 7.3C [+1.4]. The highest maximum was 14.7C on the 18th; the lowest 3.8C on the 10th. The mean minimum was 4.8C with the highest 9.1C on the 21st and lowest 0.7C on the 10th with no air frosts recorded.

Although rainfall was above average the total was modest for February totalling just under the 100 mm mark with 97.8 mm. This was (138%) & [124%] of averages and was lowest since 2015 and ranked 26th largest since 1928. The wettest day was on the 22nd with 19 wet hours and 18.0 mm rainfall. Another 17.0 mm fell on the 25th this having 15 wet hours. There were 3 (-2.6) days with no precipitation and 8 (-2.7) days were recorded as dry. Rain days were 20 and these were (+2.4) of average and wet days 14 (+2.2). Days with 5 mm, or more totalled 8 and were (=3.5) of average. Wet hours totalled 142 and the average rainfall per wet hour was 0.7 mm. At Gorwel Heights rainfall was 84.0 mm [108%] of average. The wettest day was on the 3rd with 14.2 mm and wet hours were 125 with an average fall of 0.7 mm per wet hour.

It was a dull month with only 49.2 h of sunshine recorded at RAF Valley, dullest since 2012 and ranked the 7th lowest on the Anglesey record since 1931.

Winter 2016/17

Last winter was the warmest and wettest on record in Llansadwrn. No records broken this winter, but it was the 3rd warmest on record the mean 6.7C (+1.1) & [+1.4] of averages while rainfall of 234.6 mm, lowest since 2010, ranked 19th lowest since 1928 and was (73%) & [78%] of averages.

There were 9 air frosts, lowest since 2013/14, ranking 10th in records since 1979/80.

There were 39 ground frosts, lowest since 2007, ranking 11th in records since 1985/86

Sunshine recorded at RAF Valley was 139.3 hours lowest since 2012, 8th lowest since 1931.

Winter seasonal averages Anomalies
10-y 30-y
Temperature (C)
Mean maximum 9.1 +0.9 +1.2
Mean minimum 4.3 +1.4 +1.7
Mean 6.7 +1.1 +1.4
Rainfall (mm) 234.6 73% 78 %

 

 

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March 2017

Wet and warm, but rather dull

Wettest since 2006; warmest since 2012; sunshine lowest since 2006. Brief cool spell 21 - 22nd.

With predominately 19 days with S-SW'ly winds rainfall totalled 135.6 mm and this was the largest in March since 2006 ranking 8th in Llansadwrn since 1928: 213% above the decadal average and 159 % above the 3-y average. The number of Marches with more that 100 mm is now 16, the second driest month of the year second only to April with 8 years. The wettest day was on the 30th with 19.2 mm, but the first had 17.2 mm and the 5th 13.6 mm. There were 13 days that had 5 mm or more 8.9d above average. Wet days were 9.0d above average with 20 days. There were, however, 5 days (- 4.2) with no precipitation ; 8 dry days (-7.8); 23 rain days (+7.8); and 20 wet days (+9.0). On four morning there was standing water other wise the soil was moist every day. At Gorwel Heights rainfall was 114.4 mm [132%] of average and the wettest day here was 15.4 mm on the 6th. Dry days were 10; raindays 21; wet days 18; and days with 5 mm, or more, were 10. Wet hour duration was 143 with an average of 0.8 mm per hour. In Llansadwrn wet hours were 165 with an average of 0.8 mm per hour.

A generally warm month with highest than average temperatures. The mean in Llansadwrn was 8.3C (+1.6) & [+1.3] of averages, highest since 2012 ranking 3rd since 1979. The mean maximum was 11.4C with the highest 17.4C (+1.4) on the 27th and the lowest 5.2C (-0.1) on the 5th. The mean minimum was 5.2C (+1.8) & [+1.6] again ranking 3rd. There was no air frost and there were 8 (-6.0) days with ground frost the lowest -3.8C on the 1st of the month. The mean temperature at Gorwel Heights was 9.1C [+1.7] with the highest maximum 16.5C on the 30th and the lowest 6.4C on the 5th. The mean minimum was 6.2C with the highest minimum 12.4C on the 30th and the lowest 1.6C on the 1st.

There were some very dull days with 8 of them sunless. The lowest solar radiation recorded was 1.64 MJ m -2 on the 11th while the highest was 14.97 MJ m -2 on the 25th. Sunshine at RAF Valley was 109.6h, lowest since 2006 ranking 32 on the Anglesey record since 1931. The sunniest days were on the 24th with 11.1h and the 25th 11.0h

 

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April 2017

A dry, but dull month with near average temperatures

Generally light winds from the S-W, cooler and brighter later in the month

A generally dull month with sunshine at RAF Valley 117.9h lowest since 2005 and 10th lowest on the Anglesey record since 1931. The sunniest day was on the 8th with 12.5h recorded. The highest solar radiation recorded in Llansadwrn was 23.66 MJ m -2. on the 26th and the brightest hour from 12-13 GMT was 834 W m -2 on the same day. The dullest day was on the 14th having 4.38 MJ m -2 and there were 4 sunless days.

It was a dry month with only 22.0 mm (41%) & [35%] of averages, lowest since 2010 and ranking 6th lowest in Llansadwrn since 1928. The wettest day only had 6.6 mm, the only day, that was on the 14th. Days with no precipitation were 14 (+2.4) and there were 16 dry days (0.0). Rain days were 14 (0.0) and wet days 9 (-0.5). Gorwel Heights had 26.0 mm [41%], the most in a day was 5.2 mm on the 28th.

Mean temperatures were close to the averages: in Llansadwrn 9.0C (-0.3) and [+0.1], highest since 2014, and at Gorwel Heights 9.5C [+0.6]. The highest maxima were 18.8C (+0.1) in Llansadwrn on the 8th and 16.9C at Gorwel Heights on the 9th.

 

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May 2017

Warm, dry and sunny

A spell of very warm sunny weather in the second half of the month

A very warm month with the mean temperature 13.3C (+1.8) & [+1.6] of averages, highest since 2008, the second warmest May on record at the station. The mean maximum 17.4C (+2.3) & [+1.5] of averages, also highest since 2008, ranked 7 since 1979. The highest maximum was 28.5C on the 26th and the 25th had 26.5C; there was a spell of 5 days 23 to 27th that reached 20C, or more. Minima temperatures were also above average, the mean 9.2C (+1.3) & [+1.7] was also highest since 2008. The highest minimum 16.0C on the 27th was second highest in May on record here. The lowest minimum 3.9C was on the 9th that also had the lowest grass minimum -0.5C one of the only 2 days having ground frost. Soil temperatures too were above average, at 30 cm 13.9C (+0.8) and 100 cm 12.5C (+0.4).

At Gorwel Heights the mean temperature 14.2C was [+2.6], anomaly based on 1981-2010 MetO Llanfairfechan DataPoint. The mean maximum was 18.3C with the highest 27.9C on the 26th and 10 days had 20C, or more. The mean minimum was 10.1C, the highest 16.6C was on the 27th and the lowest 5.5C on the 10th.

It was a dry month with rainfall of 48.8 mm (67%) & [79%] of averages, least since 2010, ranked 30 in Llansadwrn records since 1928, The wettest day was on the 15th having 17.2 mm. The only other day with 5 mm, or more (-2.6), was on the 12th when 10.2 mm fell. There were 16 (+5) days with no precipitation and 19 (+4.5) dry days. Rain days were 12 (-4.5) and wet days 10 (-2.5). The soil surface was dry on 18 mornings and some cracking was noted where undisturbed. Rainfall at Gorwel Heights was 28.6 mm [47%] of average. The most rain 7.6 mm fell on the 12th. There were 20 dry days; 11 rain days; 9 wet days and only 1 over 5 mm. Wet hour duration was 46 while in Llansadwrn 59 hours were recorded.

It was a very sunny month. At RAF Valley 250.0 h were recorded, (119%) & [129%] of averages, just 0.8 h behind last May 2016. It was the fifth sunniest May on the Anglesey record since 1931.

.

Spring 2016

Spring seasonal averages Anomalies
10-y 30-y
Temperature (C)
Mean maximum 13.7 +1.0 +0.7
Mean minimum 5.4 +1.1 +1.4
Mean 10.2 +1.0 +1.0
Rainfall (mm) 206.4 109% 98%

The spring mean temperature of 10.2C was highest since 2011 and was the second warmest in station records since 1979.


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June 2017

Highest June maximum 29.9C, highest mean minimum 11.8C, rainfall [212%] of 30-y average, Valley sunshine [91%]

A month of extreme contrasts, very wet first 10-d, hot day on the 21st, cloudy and dull at the end

Rainfall anomalies in June at Llansadwrn since 1929. The first 10-d were very wet with 105 mm the wettest at this station in 38 years. On the 5th 37.8 mm fell, making it the wettest day, with a further 26.0 mm on the 7th, by the end of the month 143.6 mm had fallen (176% & [212%] of averages. It was the wettest June since 1998 and 5th wettest in Llansadwrn since 1929. Rainfall at Gorwel Heights was 94.4 mm [144%]. In Llansadwrn there were 6 days with no precipitation including 5 consecutive (15-19th) and 13 (-2.5) dry days. Rain days were 17 (+2.5), wet days 14 (+2.5). There were 10 days (+5.0) with 5 mm, or more, continuing the trend for heavier falls of rain seen in recent years. Rain duration was 134 wet hours at Llansadwrn and 124 wet hours at Gorwel Heights. The latter had 15 dry days; 15 rain days; 12 wet days; and 8 days with 5 mm, or more. The wettest day there was also on the 5th with 26.0 mm.

Temperatures were all above average. The mean 15.0C [(+1.1)] was equal highest with 2015 & 2010 since 2006. The mean maximum 18.2C ranked 14 (1979) (+0.7) & [+0.4] of averages with the highest 29.9C on the 21st the highest on record in June. There was one other hot day the 19th with 26.6C and 6 days exceeded 20C with a spell of 5 on 17-21 st The lowest maximum was 12.3C on the 29th, this was 0.5C lower than the 12.8C recorded on 9th May. The mean minimum 11.8C (+1.4) & [+1.8] was highest on record in June with the highest 15.7C on the 21st 4th highest on record. The lowest minimum was 8.8C (+2.6) on the 6th was the highest on record. Temperatures at Gorwel heights were mean maximum 19.5C; mean minimum 12.6C; and mean 16.1C [+1.8]. Highest maximum 30.5C on 21st; lowest maximum 12.4C on 29th. The highest minimum was 16.2C on the 17th and lowest 8.9C on the 6th.

There were 4 consecutive sunless days at RAF Valley at the end of the month (27-30) with another on the 23rd, 5 in all. In Llansadwrn there were 7 sunless days, but we had a little on the 27th! Sunshine was 155.7h lowest since 2012 and ranked 31 on the Anglesey record since 1931. The sunniest day was on the 17th with 15.1h. The mean solar radiation in Llansadwrn was 15.41 MJ m -2 with the highest on the 17th 26.96 MJ m -2 . The lowest 2.92 MJ m -2 was on the 29th. The brightest hour was between 12 and 13 GMT on the 9th with 911 W m -2 .

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Monthly data 2017

Llansadwrn (Anglesey): Monthly weather data summary for 2017
Anomaly ~ is based on the 2007-16 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 8.1 8.9 11.4 12.4 17.4 18.2 12.7
Mean min 3.3 4.1 5.2 5.6 9.2 11.8 6.5
Mean 5.7 6.5 8.3 9.0 13.3 15.0 9.6
Anomaly~ 0.4 0.9 1.6 -0.3 1.8 1.1 0.2
Anomaly 30-y 0.6 1.2 1.3 0.1 1.6 1.1 0.4
High max 12.7 14.3 17.4 18.8 28.5 29.9 29.9
Date 30 2 27 8 26 21 .
Low max 3.7 4.2 5.2 9.5 12.8 12.3 3.7
Date 12 10 526, 28 9 29 .
High min 8.0 8.3 10.3 9.1 16.0 15.7 16.0
Date 8 18 30 9 27 21 .
Low min -1.4 -0.3 1.0 2.3 3.9 8.8 -1.4
Date 5 10 1 25 9 6 .
Grass min -6.5 -5.6 -3.8 -1.7 -0.5 5.5 -6.5
Date 5, 26 9 1 8 9 3 .
.
MSL Pressure at 09 GMT (mb) 1022 1011 1013 1023 1016 1012 1016
Highest 1039 1030 1034 1037 1030 1027 1039
Date 19 11 25 19 8 17 .
Lowest 999.7 978.8 982.6 997.0 992.7 988 979
Date 12 2 4 30 12 5 .
.
Means at 0900 GMT .
Air temperature (C) 5.2 5.7 7.9 9.2 13.5 14.8 9.4
Dew point (C) 3.8 4.3 6.1 6.8 10.4 13.0 7.4
RH% 91 90 89 85 82 90 88
Soil temperatures (C) .
.
5 cm 4.7 5.0 7.2 10 14.4 16.8 9.7
10 cm 5.0 5.4 7.3 9.6 13.3 15.9 9.4
20 cm 5.3 5.7 9.3 10.2 13.7 16.4 10.1
30 cm 6.2 6.5 8.2 10.6 13.9 16.5 10.3
Anomaly~ 0.7 0.7 1.1 0.4 0.8 0.6 -0.9
50 cm 6.8 6.9 8.3 10.6 13.5 16.2 10.4
100 cm 7.8 7.5 8.5 10.4 12.5 15.2 10.3
Anomaly~ 0.6 0.7 0.7 0.6 0.4 0.8 -1.2
.
Rainfall (mm) .
.
Rain tot 48.0 97.8 135.6 22.0 48.8 143.6 495.8
Rain % ave~ 42 138 213 41 67 176 43
Rain % 30-y 47 124 159 35 79 212 46
Days 0.0 4 3 5 14 16 6 48
Days <0.2 12 8 8 16 19 13 76
Days >=0.2 19 20 23 14 12 17 105
Days >=1.0 12 14 20 9 10 14 79
Days >=5.0 4 8 13 1 2 10 38
Max fall 9.2 18.0 19.2 6.6 17.2 37.8 37.8
Date 8 22 30 14 15 5 .
Highest rate (mm/h) 24 30 49 46 34 39 49
Date 8 23,28 30 12 31 4 .
Average rain per hour (mm) 0.6 0.7 0.8 0.4 0.8 1.1 0.8
.
Evaporation .
.
Piche (mls/ mm) 24.1 32.3 28.7 36.7 62.2 48.2 232.2
Lysimeter PE (mm) 7.5 14.5 12.8 33.5 59.2 59.4 186.9
AWS ET calculated 10.8 14.8 31.8 42.9 78.3 67.1 245.7
.
Weather (days) .
.
Air frost 4 1 0 0 0 0 5
Ground fr 14 12 8 6 2 0 42
Sl/snow 2 1 2 0 0 0 5
Sn lying 0 0 0 0 0 0 0
Thunder 0 0 1 0 0 0 1
Hail <5 mm 3 6 2 1 0 0 12
Hail >=5 mm 0 0 1 1 0 0 2
Fog at 09h 1 1 0 0 0 0 2
Gales in SE Anglesey 4 0 0 0 1 5
.
Wind direction at 09h (days) .
.
N 0 1 1 6 0 2 10
NE 4 1 3 4 10 4 26
E 0 4 2 0 4 0 10
SE 4 3 3 0 1 2 13
S 5 5 7 6 7 10 40
SW 8 11 12 5 7 9 52
W 3 3 3 4 0 2 15
NW 3 0 0 5 0 0 8
Calm 4 0 0 0 2 1 7
.
Wind speed mph .
.
Daily mean 3.2 6.7 6.3 2.4 3.5 5.4 4.6
Highest daily mean 10.1 15.2 15.0 7.8 8.4 14.4 15.2
Date 1 25 19 3 16 11 .
Mean gust 15.5 23.8 21.6 13.6 14.5 18.0 17.8
Highest gust 31 49 36 26 27 40 49
Date 9 23 17 3 16 11 .
.
AWS records of rainfall and frost .
.
Wet hours (with 0.2 mm,or more) 83 147 165 49 59 134 637
Frost duration (h) 12.3 2 0 0 0 0 14.3
.
Cloud cover at 09h. Mean % 76 80 81 80 59 83 77
.
Global solar radiation (MJ m-2) .
.
Llansadwrn
Sol rad mean 2.58 4.58 7.14 10.98 18.42 15.41 9.85
Maximum 5.97 9.19 14.97 23.66 27.92 26.96 27.92
Date 26 9 25 26 18 17 .
Minimum 0.75 1.01 1.64 4.38 4.51 2.92 0.75
Date 3 25 11 14 29 29 .
Brightest hour W/sq m 302 406 656 834 874 911 911
during hour beginning GMT 12 13 12 12 11, 13 12 12
on day 25 9 25 28 18 9 .
Sunless days 11 11 8 4 3 7 44
.
Sunshine (h) .
.
Valley 49.8 49.2 109.6 117.9 250.0 155.7 732.2
Average %~ 91 62 78 60 119 72 46
Average 30-y 86 61 97 75 129 91 51
Sunniest 7.7 7.9 11.1 12.5 15.3 15.1 15.3
Date 26 8 24 8 26 17 .
Sunless days 10 10 8 4 2 5 39
.
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 2017
# 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 9.0 9.7 12.0 12.2 18.3 19.5 13.5
Mean min 4.5 4.8 6.2 6.9 10.1 12.6 7.5
Mean 6.8 7.3 9.1 9.6 14.2 16.1 10.5
Anomaly [1981-2010] # 0.5 1.4 1.7 0.6 2.6 1.8 -0.2
.
High max 15.1 14.7 16.5 16.9 27.9 30.5 30.5
Date 31 18 30 9 26 21 .
Low max 4.8 3.8 6.4 8.3 12.4 12.4 3.8
Date 12 9, 10 5 26 8 29 .
High min 9.4 9.1 12.4 10.4 16.6 16.2 16.6
Date 7 21 30 9 27 17 .
Low min 0.6 0.7 1.6 2.6 5.5 8.9 0.6
Date 22 10 1 25 10 6 .
.
MSL Pressure at 09 GMT (mb) 1023 1012 1013 1024 1016 1012 1017
.
Highest 1039 1031 1034 1037 1030 1026 1039
Date 19 11 25 19 8 17 .
Lowest 1000 979 983 997 993 987 979
Date 12 2 4 30 12 6 .
.
Means at 0900 GMT
Air temperature (C) 6.4 6.6 8.9 9.6 14.4 16.0 8.6
Dew point (C) 3.4 4.1 5.9 5.9 9.9 12.6 43.7
RH% 82.0 84 82 78 75 81 80
.
Rainfall (mm)
.
Total 38.6 84.0 114.4 26.0 28.6 94.4 386.0
% [1981-2010] # 34 108 132 41 47 144 35
.
Max fall 6.8 14.2 15.4 5.2 7.6 26.0 26.0
Date 14 3 6 28 12 5 .
Highest rate (mm/h) 23 26 34 18 8 20 34
Date 9 21 6 28 12 5 .
.
Wet hours (with 0.2 mm, or more) 81 125 143 48 46 124 567
Average rain per hour (mm) 0.5 0.7 0.8 0.5 0.6 0.8 0.7
.
Days <0.2 10 9 10 16 20 15 80
Rain >=0.2 21 19 21 14 11 15 101
Wet >=1.0 10 14 18 8 9 12 71
Days >=5.0 2 7 10 2 1 8 30
.
Weather (days) .
.
Air frost 0 0 0 0 0 0 0
Frost duration (h) 0 0 0 0 0 0 0
Wind direction at 09h (days) .
.
N 1 1 4 4 5 4 19
NE 4 1 2 1 5 1 14
E 1 3 0 0 0 2 6
SE 6 7 4 2 5 0 24
S 2 2 2 0 3 3 12
SW 7 11 14 8 9 49
W 4 0 1 5 0 11 21
NW 0 1 0 5 0 3 9
Calm 6 2 4 5 4 2 23
4 .
Mean mph 3.2 6.7 4.2 2.2 3.5 2.8 3.8
Highest daily mean mph 7.4 18.8 8.6 10.1 7.7 7.1 18.8
Date 6 2 17 30 15 11 .
Mean gust 19.4 28.5 22.0 14.0 18.3 17.6 20.0
Highest gust 42 64 35 38 42 31 64
Date 26 2 17 30 15 5 .
.
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. I am grateful to David Lee for use of data from Gorddinog..



Designed and written by Donald Perkins © 2017

Page first dated 6 February 2017

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