- Llansadwrn data table
- Gorwel Heights data table
- January
- February
- March
- April
- May
- June
- July
- August
- September
- October
- November
- December
- Annual
- Acknowledgements
- Llansadwrn data table
- Gorwel Heights data table
Note: Values in (.) refer to the 10-y 2010-2019 average; [.] refer to the 30-y 1981-2010 climatological average while {.} refer to the station's different LTA (long-term averages). All data are subject to verification and amendment. Javascript must be enabled to see the pop-up graphics.
## January 2020## Wet, windy, mild and dull: Rainfall and temperatures well above averages, rather dull.
Rainfall totalled 154.2 mm (158%) & [151%] of averages, largest since 2016 and ranked the 13th wettest Decembers in Llansadwrn since 1928. The wettest day and raining for 18 hours was on the 11th having 32.5 mm, other wet days were the 8th with 16.0 mm and the 16th with 24.2 mm. Despite the wet days there were 3 (-1.0) that had no precipitation, dry days (having <0.2 mm) numbered 7 (-1.6). Rain days (>=0.2 mm) were 24 (1.6); wet days (>=1.0 mm) were 16 (-0.9); and days that had 5 mm, or more, 10 (3.0). Rainfall duration (wet hours) was 138 and the average rainfall per hour was 1.1 mm. Rainfall at Gorwel Heights was 126.0 mm [111%] with the wettest day on the 11th with 30.2 mm. There were 11 dry days; 20 rain days; 14 wet days and 7 had 5 mm, or more. Wet hours were 98 less than Llansadwrn, but the average rate of fall was 1.3 mm/h was greater. Temperatures were well above averages. The mean temperature at Llansadwrn was 6.4C (1.1) & [1.3] of averages, highest since 2016. The mean maximum 8.7C (1.0) & [1.1] was highest since 2016 and ranked 6th in station records since 1979. The highest maximum was 11.6C on the 7th (-0.2) closely followed by the 11.5C recorded on the 7th. The lowest maximum was 5.5C on the 9th. The mean minimum was 4.0C (1.2) & [1.4] highest since 2008 ranked 8th. The lowest minimum on the 18th was -0.2C (1.8) the only day with air frost, but that lasted for only 0.5h. There were, however, 14 (-4.0) days with ground frost equal lowest with 2016/17 since 2008, the lowest -4.5C (2.2) on the 18th. The warmth was reflected also in the soil temperatures: the mean at 30 cm 6.4C (1.0) and at 100 cm 7.9C (0.6). Temperatures at Gorwel Heights in the Llanfairfechan microclimate were remarkable for January. The mean 7.6C 1.2 degrees higher than Llansadwrn had an anomaly of [1.4] based on 1981-2010 Met Office Llanfairfechan DataPoint. The mean maximum was 10.0C with 16 days in the month of 10C, or more. A The wind direction was predominately SW'ly 15 days in Llansadwrn and 18 days at Gorwel Heights. No snow was seen in Llansadwrn, but there were 6 days when small hail (snow pellets and ice pellets) were recorded. Sunshine at RAF Valley was 48.0h (90%) & [83%] ranked 32nd lowest on the Anglesey record since 1931. The sunniest days was on the 16th and 20th with 6.1h. There were 15 sunless days
## February 2020## Wettest February on record in Llansadwrn, temperatures lowest since 2018, but mean 12th warmest over past 43-years.
Rainfall this month was 250.6 mm the largest in Llansadwrn February records back to 1928, (304%) & [319%] of averages. The largest fall was 55.3 mm on the 8th; 42.0 mm on the 19th; 28.6 mm on the 15th; 25.4 mm on the 22nd; and 23.3 mm on the 28th There was one day (-4.3) on the 6th that had no precipitation; 4 dry days (-5.8); 25 raindays (+6.6); 17 wet days (+4.5); and 10 days with 5 mm, or more (+4.5). Four days had 25 mm (1 inch), or more. There were 166h (wet) rainfall duration, the 19th had 20h of them, the 7th and 15th each 16h, the 21st 15h, the 28th 14h, all thoroughly wet days. The average rain falling per hour was 1.5 mm. Rainfall at Gorwel Heights, Llanfairfechan was a little less at 240.2 mm, largest in February and [309%] of MetO DataPoint average. The largest fall was 37 mm on the 7th with 35.4 mm on the 15th. There were 4 dry days; 25 Rain days; 21 wet days; and 9 days had 5 mm, or more. Five days had 25 mm (1 inch), or more. There were 181 wet hours duration with an average 1.3 mm/h. Rainfall at David Lee's station at Gorddinog was largest of the three stations with 285.4 mm, the largest fall 48.9 mm on the 8th. Temperatures were above average. The mean temperature 6.3C (+0.7) & [+1.1] of averages while lowest since 2018 was nevertheless 7th warmest over 42-years records. The mean maximum 8.8C (+0.3) & [+0.5] smallest of the anomalies. The highest maximum 11.4C on the 7th and 9th, the lowest 5.9C on the 11th. The mean minimum 3.8C (+1.1) & [+1.6] of averages. The highest 7.3C on the 1st and the lowest 0.4C on the 7th. There was no air frost, but there were 16 days of ground frost. The lowest was -3.8C on the 7th. At Gorwel Heights the mean temperature was 6.8C [+0.9] of average. The mean maximum was 9.2C with the highest 13.1C on the 7th and the lowest 5.2C on the 11th. The mean minimum was 4.4C with the highest 8.2C on the 15th and lowest 2.4C on the 11th and 26th. The highest maximum recorded at Gorddinog was 13.6C on the 7th. Some high gusts were recorded. At Gorwel Heights on the 8th 85 mph; 63 mph on the 9th; and 66 mph on the 15th. At Llansadwrn 57 mph was recorded on the 9th; 50 mph on the 15th; and 52 mph on the 29th. ## Winter 2019/20Largest winter rainfall since 2016, third wettest since 1928. Temperatures lowest since 2018, but the mean 6.5C ranked 7th warmest over the past 42-years
## March 2020## Near average rainfall and temperatures hides the true picture.
Rainfall of 85.7 mm (104%) and [101%] of averages, lowest since 2016, but ranking 29th largest since 1928, hid the fact that the last 14 days had no significant rain, 12 days were perfectly dry. The largest fall was on the 17th having 22.2 mm. Days with no precipitation were 13 (+5.8); dry days were 16 (+3.0); rain days 15 (-3.0); wet days 10 (-4.6); and days with 5 mm, or more, 5 (-3.4). Rainfall at Gorwel Heights was 78.4 mm [91%] of average. The largest fall was 29.8 mm on the 17th. Dry days wee 18; rain days 13; wet days 9; and there were 5 days that at 5 mm, or more. The mean temperature was 7.0C (+0.2) & [0.0] of averages, lowest since 2018, ranking 19th lowest in station records since 1979. The mean maximum 10.4C ranked even lower 24th, the highest maximum 18.1C on the 25th stood out in the month. The lowest maximum was 6.6C on the 18th. The mean minimum was 3.5C and the lowest minimum 0.2C on the 2nd so no air frosts. The lowest grass minimum was -5.0C on the 2nd and there were 13 ground frosts. At Gorwel heights the mean temperature was 7.6C [+0.2] of average. The mean maximum was 10.6C with the highest 17.6C on the 24th. The mean minimum was 4.6C with the lowest minimum 2.0C on the 6th.
## April 2020## Very sunny, warmest since 2011 and driest since 2010.
Sunny. Sunshine recorded at RAF Valley was 215.8h most since 2015 that was the sunniest April on the Anglesey record back to 1931. This year ranked the 5th sunniest. Two sunniest days the 20th and 21st each 13.0h. The 28th was the only sunless day. Until the 17th there had only been 1.9 mm of rain and it looked as if the month was challenging the record low of 6.7 mm here in 1980 the second year of observations at the station. This was not to happen as 7.2 mm fell on the 17th, a fall not seen in Llanfairfechan (GH) where only 3.8 mm had fallen by the 27th, and a wet end to the month brought the total up to 25.1 mm here and 23.4 mm at Gorwel Heights. The 25.4 mm was (47%) &[40%] of averages ranked 9th lowest in Llansadwrn since 1928. There was no precipitation on 20 days (+8.7); and there were 22 dry (< 0.2 mm) days (+7.8). Rain days were 8 (-7.8); wet days 5 (-6.1); and just 2 days (-4.2) with 5 mm, or more. The wettest day was on the 29th with 7.8 mm. Rainfall at Gorwel Heights 23.4 mm was [37%] of average with the most 12.8 mm falling on the 29th. There were 22 dry days; 8 rain days; 5 wet days and only 1 had 5 mm, or more. Rainfall duration (wet hours) was 37 at Llansadwrn and 34 at Gorwel Heights. Soil moisture under grass (2-8 cm) determined on the 21st was 39.1% dry mass down from 43.8% dm on the 8th. The top 2 cm consisting of mainly compacted roots and grass containing most of the moisture was 46% dm, down from 69% dm on the 8th. On the undisturbed met plot 0-8 cm deep was 15.2%, similar to that at the beginning o the month. On the vegetable plot, that has a larger organic matter content (not irrigated), 0-8 cm was 20.7% dm and 8-14 cm was 24.5% dm. The permanent wilting percentage for the soil here is 15% dm. We have had a very dry event. It is remarkable that this situation arose so quickly after the wet months of February and March, this is not only due to having had just 8.8 mm by the 21st, but also above average temperatures and high evaporation rates. The month ended with a PE (Potential Evaporation) of 106.7 mm and a calculated ET of 71.0 mm The PWB (Potential Water Balance] by lysimeter was -81 6 mm. The mean temperature 11.1C (+1.9) & [2.2] of averages highest since 2011 was the third highest in station records. The mean maximum 15.5C (+2.5) & [+2.6] of averages was the second highest. Highest maximum on the 10th was 22.4C (+3.0) was lowest since 2017, but ranked sixth highest. The mean minimum 6.7C (+1.3) & [+1.8] of averages ranked fourth with the lowest 1.5C on the 14th. There was one ground frost of -1.4C on the 14th. At Gorwel Heights the mean temperature was 11.5C [+2.7] with the highest on the 5th was 21.9C. The mean minimum was 7.6C with the highest on the 10th 11.9C and the lowest on the 14th 3.2C.
## May 2020## Driest and sunniest May on record.
With just 11.9 mm of rainfall it was the driest May in Llansadwrn since before 1928 when records began. Just (17%) & [19%] of averages we had 22 (+10.1) days with no precipitation what so ever. Dry days were 26 (+10.6); rain days only 5 (-10.6); wet days 3 (-7.6) and just one day with 5 mm, or more, in fact the only day 5.8 mm on the 21st. It was even drier in Llanfairfechan where at Gorwel Heights just 7.8 mm were recorded [xx]. The largest fall was 4.8 mm on the 21st. Sunshine at RAF Valley 312.3h We had two hot days on the 29th with 25.3C and 25.4C on the 30th not quite getting three to call it a heatwave as the 30th had 22.6C and the 28th 23.2C. The mean maximum was 17.1C (+1.8) & [+1.2] of averages; the mean minimum 2.2C (+.3) & [+0.7] of averages; and the mean 12.7C (+1.1) & [+0.9] of averages, highest since 2017 ranking 7th warmest over the last 40 years. The lowest minimum was 2.0C on the 12th that also had the lowest grass minimum -2.7C. There were 3 days of ground frosts (+1.6). At Gorwel Heights the highest maximum was 24.7C on both the 29th and 30th with highest minima 15.6C on both the 30th and 31st. ## Spring 2020A very dry April and May meant that the rainfall total 122.7 mm was fourth driest on record in Llansadwrn since before 1928. Drier springs were 1990 with 80.2 mm, 1984 with 110.7 mm, and 1974 99.6 mm. Temperatures were above the averages and the mean 10.2C was second highest on record only beaten by 2011 that had a mean just 0.2C higher at 10.4C. It was the
## June 2020## A dull and wet month with temperatures a little above average. A record 31.3C.
A record temperature for June of 31.3C was recorded on the 25th with means a little above average. The monthly mean was 14.7C (+0.5) & [+0.8] of averages, highest since 2018 and 12th in the record book since 1979. The mean maximum was 18.2C [(+0.4)] and the mean minimum 11.3C (+0.6) & [+1.3] of averages, the highest minimum was 16.4 on the 26th and the lowest 5.9C on the 8th that also had the lowest grass minimum of 1.8C (-1.5). The earth 30 cm depth average was 15.7C (-0.2) and the 100 cm 14.4C on the button (0.0). At Gorwel Heights the mean temperature was 15.1C [+0.9]. The highest maximum was 30.1C on the 25th and the lowest 11.6C on the 3rd. The mean minimum was 11.9C, the highest minimum was 17.3 on the 26th and the lowest 6.7C on the 6th. A wet month. Rainfall at Llansadwrn was 102.4 mm (133%) & [151%] of averages, largest since 2017 and ranking 19th in records back to 1929. The wettest day was on the 14th with 14.4 mm. There were 3 days (-9.5) with no precipitation; dry days were 8 (-8.0); rain days 22 (+8.0); wet days 17 (+6.4) and days with 5 mm, or more, significantly 8 (+3.4) the trend being upward in recent years. Wetter at Gorwel heights where 118.4 mm fell [181%] of local average. The wettest day was on the 28th when 19.2 mm fell. Dry days were 9; rain days 21; wet days 18 and days with 5 mm, or more, significantly 9. It was an unusually thundery month with 7 days of storms observed often with vivid lightning, the 14-17th and 25-27th inclusive. A rather dull month with 137.6 h of sunshine recorded at RAF Valley, lowest since 2002 and 9th lowest in June on the Anglesey record back to 1931. The sunniest day was on the 1st having 15.5h sunshine. There were just 6 days with 10h, or more, there was one sunless day, but 10 saw less than 1h each day. ## July 2020## Wettest since 2010 and 2nd wettest July on record in Llansadwrn since 1928; coolest since 2012 rank 7th in station records since 1979; dullest since 2012 at Valley rank 17th on Anglesey record since 1931.
A soaker of month the 179.6 mm (205%) & [257%] of averages, wettest since 2010 with 182.1 mm the largest in July in 92-year Llansadwrn records back to 1928. The largest fall was 35.5 mm on the 3rd, most in a July day since 1988 (36.8 mm on the 28th) ranking second, and the 31st largest overall out of 14960 daily records. There were 5 days (-4.9) with no precipitation and 7 dry days (-6.0); 24 rain days (+6.0); 18 wet days (+4.5); and significantly 13 days had 5 mm, or more, a trend associated with climate heating. Rainfall at Gorwel Heights totalled 128.2 mm, the largest fall in July since 2012 (142.1 mm). Most was on the 8th with 20.0 mm; dry days were 7; rain days were 24; wet days 18; and 9 had 5 mm, or more. A somewhat cool month for July with a mean temperature 14.6C, lowest since 2012, and ranking 7th lowest in station records since 1979. The mean maximum was 17.6C (-1.8) & [-1.9] of averages, if it was not for the last 2 days the maximum would have been 19.4C on the 24th, but just in time we had 27.4C (-0.9) on the 31st and the 30th was credited with 25.7C as it occurred at 0900 GMT. Low maxima occurred on the 17th and 27th each 13.8C (-0.9). The mean minimum was 11.7C (-1.3) & [-1.1] of averages, the lowest was a cool 7.8C (-1.1) on the 10th that also had a 4.4C grass minimum only to be outdone the next day the 11th with 3.8C and heavy dew. A rather dull month overall. Sunshine at RAF Valley totalled 128.1h (provisional) least since 2012. It was the 17th dullest July on the Anglesey record. Lower than average sunshine totals are not unexpected in July more's the pity (graphic left), really sunny Julys with 50 hours anomaly, or more, with ten are rather rare. Only 4 days had 10h, or more, the 10th had 10.0h; 11th had 12.4h; the 19th 13.1h was the sunniest; and the 20th 12.2h. Fourteen days saw 1.0h, or less, of which 7 were sunless. Llansadwrn had 10 sunless days with the lowest solar radiation 3.51 MJ m The month was notable for the absence of thunder and hail, and its number of foggy days 7 when the island was often enveloped in low cloud when bright and sunny in Llanfairfechan... ## August 2020## Wettest August in Llansadwrn since 1961 and 4th wettest August on record since 1928; warmest since 2004 ranking 8th in station records since 1979; dullest since 2018 at Valley ranking 40th on Anglesey record since 1931.
A very wet month with 168.5 mm of rainfall (183%) & [194%] of averages. Largest in August since 1961 and ranking 4th in Llansadwrn records back to 1928. Llansadwrn rainfall in 1961 was 190.8 mm at It was a generally warm month, the mean in Llansadwrn was 16.4C (+1.2) & [+0.8] of averages, equal highest with 2019 since 2004, but off the absolute highest mean 18.7C in 1995. The mean maximum was 19.4C, equal to 2019 and 2016, highest since 2005 (19.8C). There were 12 warm days (>=20C) with a spell of 9 days 7-15th all in the first 20 days. The highest maximum was 25.5C on the 11th, the only hot day, but two days reached 24.9C and 24.8C on the 12th and 13th. The lowest maximum was 14.7C on the 27th this reflecting the cooler last 11 days. The mean minimum was 13.3C (+1.1) & [+1.3] of averages, the lowest 6.9C (-1.2) on the 31st, reflecting the rather chilly unseasonable end to the month, equal lowest with 2014 since 1993 (6.5C). The lowest grass minimum 2.5C also occurred on the 31st, the Thunderstorms occurred on 4 days, 10th, 11th, 12th and 21st, but no hail was observed in the month. It was a dull month overall with 155 hours of sunshine and 5 sunless days recorded at RAF Valley. The sunniest day was on the 8th with 13.6h followed by 12.6h on the 9th. Overall there were 6 days with 10h, or more. In Llansadwrn the mean solar radiation was 12.20 MJ m
## Summer 2020## Wet and dull, mean temperature a little above averageThe 450.5 mm of rainfall, (176% & [202%] of averages, made it the wettest summer in Llansadwrn since records began in 1928 The mean summer temperature 15.3C was lowest since the 16.4C in 2018, but ranked 14th highest in 42-years of station records. After the sunniest spring on record it was the dullest summer since 2004. Sunshine at RAF Valley was 420.7h (provisional), (71%) & [64%] of averages, ranking 14 on the Anglesey record since 1931.
## September 2020## Driest and sunniest month since May with near average temperatures overall
The mean temperature 14.0C was close to averages (+0.2) & [+0.1] hiding the warm days and unusually cool ending to the month. There were 5 warm days >=20C the highest 24.8C on the 14th and 5 cool days <=15C the lowest 11.3C on the 24th. The mean maximum 17.5C equalled last year 2019 and was the 17th highest at this station since 1979, whereas the mean minimum 10.4C, lowest since 2015, ranked 19th lowest. The lowest minimum was 6.3C on the 24th and the lowest grass minimum 2.3C (-0.1) on the 27th lowest since 2018. It is by no means the lowest September grass minimum as 2014 and 2015 both had zero. At Gorwel Heights the mean temperature was 14.8C [+0.4] the highest 21.0C on the 15th. The mean maximum was 18.2 C with the highest 24.7C on the 8th and the lowest 12.2C on the 26th. There were 9 warm days >=20C with a spell of 5 days 13-17th. The mean minimum was 11.4C with the highest 17.6C on the 13th and the lowest 7.4C on the 25th. September was the driest month since May this year having 71.5 mm (65%) & [75%] of averages and lowest since 2015 ranking 26th since 1928. The wettest day was on the 22nd having 22.2 mm, but there was 15.2 mm on the 2nd. There were 10 (+1.5) days with no precipitation and 15 dry days. There were 15 (+6.5) rain days and 13 (-3.3) wet days. Number of days with 5 mm, or more, were 3 (-3.8). It was a little wetter at Gorwel Heights with 82.6 mm [85%] of DataPoint average. The wettest day was on the 22nd it having 29.2 mm. Here number of days with 5 mm, or more, were six. Dry days were 17; rain days 13; and wet days 10. It was the sunniest since May a RAF Valley the 158.8 hours highest since 2015 and ranking 13th sunniest September on the Anglesey record since 1931. The sunniest day was on the 18th having 11.2h, 5 days saw 10h or more whilst 6 days saw <1h. There were 4 sunless days. Global solar radiation in Llansadwrn averaged 9.86 MJ m
## October 2020## Very wet with temperatures below the decadal averages, but close to the 30-y average.
A very wet month with rainfall of 186.3 mm (159%) & [145%] of averages, largest since 2012 and 12th largest in Llansadwrn records since 1928. It was much wetter in Llanfairfechan where at Gorwel Heights 273.0 mm was recorded [217%] of average. Wettest days in Llansadwrn were 33.6 mm on the 3rd; 24.3 mm on the 24th; and 33.9 mm on the 29th. At Gorwel Heights 60.6 mm fell on the 3rd resulting in local flash flooding in the village of Llanfairfechan; 28.8 mm on the 7th; 24.8 mm on the 12th; 21.2 mm on the 24th; and 34.8 mm on the 29th. In Llansadwrn there were just 3 days (-4.0) without any precipitation and 7 dry days (-3.7). There were 24 rain days (+3.7); 19 wet days (+4.4); and 8 days (+0.4) had 5 mm, or more. At Gorwel Heights there were 6 dry days; 25 rain days; 20 wet days; and 11 days had 5 mm, or more. Rainfall duration in Llansadwrn was 159h and was 192h at Gorwel Heights. Temperatures were below averages of the last decade, but close to the climatological 30-year averages [1971-2010] these of course will be updated in January 2021. The mean temperature in Llansadwrn was 10.8C (-0.6) and [-0.1], highest since 2018 and ranking 18th in station records since 1979. The maximum 13.4C, however, showed the greatest anomaly being (-0.5) & [-0.6] while the lowest 8.1C was (-0.6) & [+0.4]. The highest maximum was 16.8C on the 20th and the lowest 11.4C just 2 days later on the 22nd. The lowest minimum 5.4C was on the 10th this being (+1.6) of the decadal average. There was no ground frost the lowest was 0.3C on the 15th and this was (+0.9) of average. At Gorwel Heights the mean temperature was 10.9C [-0.7] with the highest maximum 17.2C on the 19th and the lowest minimum 6.4C on the 25th. Sunshine recorded at RAF Valley totalled 90.6h lowest in October since 2017, this was 'middle of the road' on the Anglesey sunshine record since 1931. The sunniest day with 9.0h was on the 15th and there were 4 sunless days. The brightest day in Llansadwrn was on the 1st of the month with 10.05 MJ m ## November 2020## Warm, but dull and rather wet.
The month began terribly wet with 48.6 mm falling in Llansadwrn and 57 .0 mm at Gorwel heights on the first day. Total rainfall in Llansadwrn was 155.4 mm (122%) & [123%] of averages, largest since 2017 and ranking 25th in Llansadwrn records since 1928. At Gorwel Heights, Llanfairfechan, 147.6 mm fell [109%] of average. Rainfall duration was 141 h in Llansadwrn with an average fall of 1.1 mm/h and 122 h at Gorwel Heights at an average 1.2 mm/h. In Llansadwrn there were just 2 days (-1.8) without any precipitation and 7 dry days (-0.7). Rain days were 23 (+0.7); wet days 17 (+0.1); and there were 9 days that had 5 mm, or more. Quite an average month. Despite the poor weather it was a warm month overall the mean temperature 9.2C was 1.5 degrees above the 30-y climatological average. Despite this it was on the average of what we have had in the last decade. The highest maximum 16.1C was on the 9th and the lowest 9.3C that was 3.1 degrees above the decadal average. The lowest minimum of 1.5C on the 28th was a degree above the average and the lowest grass minimum -3.1C was about average. There was 7 (-1.3) ground frosts. At Gorwel Heights the mean temperature was 10.0C [+1.1] with the highest 14.1C on the 9th and 14.0C on the 18th. The mean maximum was 12.5C with the highest 17.6 C on the 9th and lowest 8.1C on the 3rd. The mean minimum was 7.4C with the highest 12.4C on the 18th and lowest 4.4C on the 28th. It was a rather dull month with just 44.3h of sunshine recorded at RAF Valley lowest since 2015 and 19th lowest on the Anglesey record since 1931. The sunniest day was on the 6th having 7.9h, it was also the brightest day in Llansadwrn where solar radiation was 7.17 MJ m ## Autumn 2020
Wetter than average, less than in 2018 ranking 18th largest in Llansadwrn since 1928. Warmest since 2015 and ranking 12th in station records since 1979. The mean temperature was just below last decadal average, but 0.5 degrees above the 30y climatological average. ## December 2020## Dull and wet, temperatures lower than over the past decade.
Rainfall was 183.4 mm largest since the record breaking December 2015 (415.8 mm) and was 117% of the decadal average, but 152% of the 1981-2010 climatological average. It was the 12th wettest December in Llansadwrn since records began in 1928. Despite the large rainfall there were no significantly large daily falls. The wettest day on the 14th had just 14.4 mm. There were 5 days with 10 mm, or more, and 19 with 5 mm, or more, this (+9.1) of average. There were no days with no precipitation (-3.5) and just 2 dry days (-1.5). There were 29 (+5.1) rain days and 26 (+7.3) wet days. It was wetter in Llanfairfechan, at Gorwel Heights rainfall was 223.0 mm [170%] of average, again wettest since 2015 (310.2 mm). It was the 4th wettest of any month recorded at the station since 2011. Just 1 dry day; 30 days of rain; 28 wet days; and 17 days had 5 mm, or more. Here there wettest day was the 15th with 18.0 mm. Rainfall duration (wet hours) was 250 (0.9 mm/h) in Llanfairfechan and 247 (0.7 mm/h) in Llansadwrn. Temperatures were lower than the last decade, but above the 30y average. It had been a cooler and more wintry December than we have had of late. The mean temperature 5.9C (-0.6) & [+0.5] of averages was equal lowest with 2017 back to 2012. The mean maximum 7.9C (-0.9) & [+0.1] of averages was lowest since 2010 (4.3C) lowest in station records. The highest maximum was 13.8C on the 19th and the lowest 3.3C on the 30th. The mean minimum 3.8C (-0.6) & [+0.5] was lowest since 2017. The highest minimum was 7.6C (-2.0) occurred on 3 days the 14th, 18th and 19th. The lowest minimum was -0.4C on the 31st recording the only air frost of 3.7h duration. There were 19 (+5.8) ground frosts, most since 2104, the lowest -5.5C on the 31st. At Gorwel Heights a temperature of 15.1C was recorded on the 18th, highest of the month. The mean maximum was 8.3C and the mean minimum 4.6C, the lowest 0.9C on the 31st once again escaping an air frost. The mean temperature was 6.5C [-0.1] of average. A wintry month with 19 days (+5.9) of small hail that included snow pellets and ice pellets, the most in December since 2011. Sleet and or snow fell on 2 days (-0.5) the 30th and 31st. A pretty dull month with sunshine 34.4h recorded at RAF Valley, lowest since 2018. The sunniest day was on the 6th having 5.6h. Twenty days saw less than 1h of sunshine and 11 were sunless compared with 7 in Llansadwrn.
## Annual 2020## Wettest year on record at this station and in Llansadwrn back to 1928
## Monthly data 2020
## Llanfairfechan, Gorwel Heights observations
## AcknowledgementsThe Met Office at RAF Valley kindly supplied observational data from 1942 to 2011. Current data (provisional) are gathered from SYNOP reports and METAR, any missing observations are initially derived from nearby stations to complete the record, up to date figures are later gathered from the Met Office website. 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 additional observations.
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