Llansadwrn (Anglesey) Weather:
Monthly and Annual
Summary for 2024

• Llansadwrn data table
• Gorwel Heights data table

• January
• February
• Winter
• March
• April
• May
  • Spring
• June
• July
• August
  • Summer
• September
• October
• November
  • Autumn
  
  
• Acknowledgements

• Llansadwrn data table
• Gorwel Heights data table

   

  Note: Values in (.) refer to the 10-y 2014-2023 average; [.] refer to the 30-y 1991-2020 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, as of date this works best with Firefox and. Chrome browsers..

  

January 2024

February 2024

March 2024

An atypical month. Wet with below average sunshine and above average temperatures

April 2024

A wet month, but driest since 2019. Temperatures above average, sometimes windy. Sunshine below average.

Rainfall was 91.0 mm, not reaching 100 mm that eight Aprils have had in Llansadwrn since 1928, largest since 2012 ranking 15th. This was [129%] of the 30y average, but (201%) of the last decade reflecting drier Aprils in recent years. The largest fall was a modest 14.6 mm on the 8th and 6 days (-8.1) had no precipitation. Dry days numbered 10 (-6.8); rain days were 20 (+6.8); wet days 16 (+6.8); and there were 7 days (+3.5) with 5 mm, or more.

At Gorwel Heights in Llanfairfechan rainfall was 97.6 mm largest since 2018, the wettest day was on the 5th with 21.2 mm and the 8th with 20.0 mm not far behind. These were the only two days to exceed 10 mm and made up 42% of the month's total. There were 8 dry days; 22 raindays; 14 wet days; and 7 reached 5 mm, or more. Rainfall duration (wet hours) was 112 h and in Llansadwrn 125h.

Temperatures were above the average, particularly the minima while the maxima struggled to reach the normal. In Llansadwrn the mean was 9.7C highest since 2020 ranking 10th highest in station records, (+0.3) & [+0.6] of averages. The mean minimum was 6.6C (+0.9) & [+1.0] of averages, the highest was 11.4C on the 6th (+1.6) and lowest 2.6C on the 26th (+1.5). The mean maximum 12.9C, (-0.4) & [+0.1] of averages, lowest since 2021 ranked 22nd warmest in records since 1979, the highest maximum 18.9C on the 5th was (-1.3), the lowest maximum 2.8C on the 26th was (+1.4). The was no air frost and just 3 days (-4.1) of ground frost, lowest -0.7C on the 10th.

At Gorwel Heights the mean temperature was 10.1C (+0.5) & [+0.5] of averages, highest equal with 2022 since 2020. The highest mean was on the 11th with 15.0C and the lowest 6.5C on the 26th. The mean maximum was 12.9C, lowest since 2021, the highest 20.7C on the 5th and the lowest 9.3C on the 26th. The mean minimum was 7.2C, the highest 12.6C on the 6th and lowest 3.6C on the 26th

Sunshine at RAF Valley was a provisional 138.0h, lowest since 2019. The sunniest day was on the 20th having 12.8h, 5 days had 10h, or more,and there were 2 sunless days. Rainfall was 82.8 mm.

The mean temperature 14.0C was the highest in May at this station since records began in 1979 and a huge (+1.9) & [+2.2] of averages. The mean minimum 10.4C, highest since before 1979 reaching double figures for the first time with even larger anomalies (+2.1) & [+2.5]. The mean maximum 17.5C was highest since 1992 and ranked fourth highest in records. The highest maximum on the 11th was 25.4C (+3.8), not unusual for May, was equal highest with 2020 since 2017. Five days reached, or exceeded 20C. The lowest maximum was 10.6C on the 23rd. The highest minimum was 14.5C on the 12th while the lowest 6.3C was on the 1st. There were no ground frosts.

At Gorwel Heights the mean temperature 14.0C was highest on record since 2011. The mean maximum was 17.2C with the highest maximum 25.2C on the 11th and the lowest 10.9C on the 23rd. The mean minimum was 10.8C and highest on record though reaching double figures twice in the past in May. The lowest minimum was 7.6C on the 25th.

The graphic left, shows anomalies from the 30-year May mean of 11.8C, computed using a comparatively extended data series back to 1942, from 1978 using Valley observations. Llansadwrn onsite data are used from 1979. The 2024 exceeds the previous greatest anomaly in 2008 13.6C by 0.4C

May was wetter than usual with 87.6 mm recorded in Llansadwrn (124%) & [129%] of averages, largest since 2021 ranking 21 since 1928. The largest fall was on the 22nd with 22.4 mm. There was a week (5-11th) of dry weather at the beginning of the month and overall there were 14 days without precipitation. There was 17 dry days; 14 rain days; 11 wet days; and 9 days had 5 mm, or more. Rain duration was 101h (wet hours).

It was wetter at Gorwel Heights with a not unusual 117.6 mm of rain. The wettest day was on the 22nd when 37.6 mm fell. Dry days numbered 18; rain days 13; wet days were 12; and 9 reached 5 mm, or more. Rain duration (wet hours) here was 106 h.

It was a dull month. Sunshine at RAF Valley was 172.4h (provisional) least since 2014, (76%) & [85%] of averages. The sunniest day with 12.8h sunshine was on the 11th and there ware 5 sunless days.

June 2024

Cool. drier than usual and fairly sunny

Temperatures were below averages for the first time this year and had greater anomalies since May 2021. Greatest anomalies were with the decadal averages less so with the 30y averages. The mean 12.6C (-1.3) & [-0.5] of averages was equal lowest since 2014. The mean maximum 17.1C (-1.5) & [-0.6] was equal lowest since 1012 ranking 14th lowest in station records since 1979. The highest maximum 25.6C was on the 26th and the lowest 13.6C on the 9th. The mean minimum 10.0C (-1.3) & [-0.5] was lowest since 2015 ranking 22nd lowest. The lowest grass minimum 4.1C on the 5th a rare (+0.5) of average.

Temperatures at Gorwel heights, Llanfairfechan, were similarly below average. The mean 14.3C equal lowest since 2011 when records began was (-1.4) & [-0.6] of averages. The mean maximum 17.7C was lowest since 2012 with the highest 26.2C on the 26th and the lowest 13.9C on the 9th. The mean minimum 10.9C was equal lowest with 2021. The highest was 14.5C on the 23rd and lowest 7.3C on the 5th.

Rainfall was blow average, but was characterised by long spells of slight rain and drizzle particularly in Llansadwrn when the island was enveloped in low cloud/ fog. The wet hour duration values were 94h in Llansadwrn and 50h at Gorwel Heights. Rainfall totals were not dissimilar and most since 2020, 48.9 mm in Llansadwrn, ranking 32 lowest since 1928 and 46.4 mm at Gorwel Heights. Greatest falls were 11.8 mm on the 9th in Llansadwrn and 19.8 mm on the 9th at Gorwel Heights. In Llansadwrn there were 5 days with no precipitation (-7.3); 10 dry days (-5.9); 20 rain days (+5.9); 14 wet days (+3.9); and 3 days (-1.4) had 5 mm, or more. At Gorwel Heights there were 15 dry days; 15 rain days; 7 wet days; and 3 days had 5 mm, or more.

Sunshine at RAF Valley 215.1h (provisonal) was [115%] of the 30y climatological average, but (97%) of the last decade's average, ranking H21st on the Anglesey record back to 1931. The sunniest day was on the 24th having 13.4h and there were 2 sunless days.

July 2023

A month of below average temperatures with more rainfall and less sunshine than usual

Coolest since 2020 with the mean temperature 15.2 (-0.9) & [-0.6] of averages. The mean maximum was 18.7C (-1.0) & [-0.6] of averages with the highest maximum 24.1C on the 29th (-4.0) and lowest 14.7C on the 11th (-0.4). The mean minimum was 11.8C (-0.8) & [-0.5] with the lowest 7.8C (-1.3) on the 8th that also had the lowest grass minimum of 4.2C (-1.3).

At Gorwel Heights, Llanfairfechan, the mean temperature also lowest since 2020 was 15.9C (-1.1) & [-0.8] of averages with the highest 24.2C on the 19th and lowest 14.8C on the 11th. Gorddinog recorded 24.9C on the 19th. The mean minimum was 12.5C with the lowest 8.7C on the 8th.

Rainfall was above average with 102.4 mm (114%) & [132%] of averages falling in Llansadwrn least since 2022 ranking 24th largest in records since 1928. The largest fall 17.8 mm was on the 5th, but 13.0 mm fell next day on the 6th. There was a dry spell of 5-days at the end of the month (26-30th). Days with no precipitation numbered 8 (-1.5) and there were 12 dry days (-1.1). Rain days were 19, wet days 15, and 7 days had 5 mm, or more. Rain fall duration (wet hours) was 120 h. It was wetter at Gorwel Heights where 148.4 mm fell (161%) & [186%] of averages. The largest fall 35.4 mm on the 22nd was second largest on record less than the 47.4 mm recorded in July 2012. There were 10 dry days; 21 rain days; 13 wet days; and 9 had 5 mm, or more. Rainfall duration (wet hours) was 101 h. Rainfal;l at Gorddinog was 96.5 mm with the largest fall 17.3 mm on the 11th.

It was a rather dull month particularly in Llansadwrn with 7 sunless days. Sunshine at RAF Valley was 96.5h (provisional) (85%) & [94%] of averages. The sunniest day was on the 28th with 14.0h, there were 3 sunless days..

August 2024

Close to average rainfall, significantly drier in Llanfairfechan. Temperatures and sunshine above averages

Rainfall was 86.4 mm (88%) & [96%] of averages, largest since 2022 ranking 46 least since 1928. The largest fall was 14.8 mm on the 5th. There were 9 (+1.6) days with no precipitation; 14 (+1.3) dry days; 17 (-1.3) rain days; 12 (-1.2) wet days; and 7 days (+2.0) had 5 mm, or more. Rainfall duration (wet hours) was 92 h.

Gorwel Heights had 46.0 mm (43%) & [52%] of averages, the driest recorded here since records began in 2011. Gorddinog was drier reporting 41.0 mm. The wettest day at Gorwel was the 22nd with 10.4 mm when Gorddinog had 7.3 mm. At Gorwel there were 13 dry days; 18 rain days; 10 wet days; and 4 reached 5 mm, or more. Rainfall duration was 80 h.

Temperatures were above averages. At Llansadwrn the mean was 16.1C (+0.3) & [+0.5] and at Gorwel Heights 17.5C (+0.8) & [0.9] of averages. Highest were 26.1C in Llansadwrn on the 11th and 27.3C at Gorwel Heights

Sunshine at RAF Valley was 189.6h (MetO provisional) most since 2022 and despite 6 sunless days ranked 11th highest in Anglesey records since 1931. The sunniest day was on the 31st having 12.1h.

Summer 2024

It was the coolest summer since 2015.

It was the driest summer since 2022, close to the averages rank 46 largest rainfall since 1928 in Llansadwrn, but driest in Llanfairfechan Gorwel since before 2011.

September 2024

Wettest September since 1976, a station record (since 1979). Temperatures a little below averages.

Some very wet days throughout, cooler days with thunder and hail towards the middle

Rainfall 178.3 mm, (173%) & [176%] of averages, was a station record for September and largest in Llansadwrn records since 1957, rank 6th largest since 1928. The wettest day was on the 1st with 54.4 mm falling and the last two combined had 44.2 mm. There were 146 wet hours duration with an average 1.3 mm falling per hour. It was not all wet, however, as 8 days (-1.1) had no precipitation and there were 14 dry days (+4.9). Rain days were 16 (-1.4) and near average wet days 13 (+0.3) while 8 days had 5 mm, or more. The month's rain brought the total for the year (right) up to 1032.2 mm, most since 2020 and third largest in Llansadwrn records since 1928. Wettest was 1957 having 1068.7 mm accumulated by the end of September.

Gorwel Heights was wetter having 204.8 mm (196%) & [214%] of averages, least since 2023 that had 216.4 mm. The largest fall of 35.8 mm was on the 1st while 28.6 mm fell on the 26th and the last two days 12.4 mm and 31.8 mm. here there were 9 dry days; 21 rain days; 17 wet days; and 11 had 5 mm, or more.

The mean temperature in Llansadwrn was 13.8C (-0.76) & [-0.2] of averages, lowest since 2018 and ranking 22nd highest since 1979. The maxima had the largest negative anomalies with the mean (-1.1) & [-0.5] with the highest maximum 23.4C on the 7th and the lowest 12.3C on the 30th. The mean minimum was 10.9C (-0.4) & [+0.2] of averages, the lowest minimum was 5.9C on the 28th while the lowest grass minimum was 2.6C on the 28th.

At Gorwel Heights the mean minimum was 14.3C (-1.0) & [-0.6] of averages, lowest since 2018. The mean maximum was 16.7C with the highest 22.7C on the 19th and lowest 12.5C on the 30th. The mean minimum was 11.7C with the highest 17.4C on the 7th and lowest 7.4C on the 13th.

Thunder was heard on the 11th at 1227 GMT, just before at 1212 GMT there had been a shower of 2-3 mm ice pellets. Ice pellets fell also on the 12th and 15th the three occasions in the month more than usual (+2.4).

October 2024

Drier than usual and rarely <100 mm, temperatures a bit above averages.

Above average sunshine at the beginning, very dull with large number of sunless days at the end.

Total rainfall was 91.8 mm (62%) & [71%] of averages, least since 2016, and one of the 30 drier Octobers on the Llansadwrn record since 1928. There have been 63 Octobers that have returned more than 100 mm, highest this station 282.8 mm in 2008 and lowest 37.9 in 2016. Lowest on the Llansadwrn record was in 1946 with 8.6 mm (at Gadlys Cottage) and 17.3 mm (at Treffos). The wettest day was on the 27th with 21.0 mm, but 16.0 mm fell on the 16th. There were 7 days (+0.8) with no precipitation; 12 (+2.3) dry days; 19 (-2.1) rain days; 14 (-2.2) wet days; and 7 (-1.3) days had 5 mm, or more. Rainfall at Gorwel Heights was 94.6 mm (64%) & [75%] of averages the most 13.6 mm falling on the 25th. There were 14 dry days; 17 rain days; 13 wet days; and 9 days had 5 mm, or more. Rainfall duration (wet hours) was 95h while Llansadwrn recorded 91h.

The monthly mean temperature in Llansadwrn was 12.0C (+0.3) & [+0.9] of averages, lowest since 2020 ranking 13th highest since 1979. The mean maximum was 14.9C with the highest 18.3C on the 5th (-1.3) and the lowest 10.4C on the 13th (-0.4). The mean minimum was 9.0C with the lowest 3.5C on the 13th. There were no ground frosts the temperature on the grass falling to 0.0C on the 11th and 13th. At Gorwel Heights the mean temperature was 12.7C (+0.3) & [+0.8] of averages. The mean maximum was 15.4C with the highest 19.4C on the 7th and the lowest 10.6C on the 10th. The mean minimum was 10.0C with the highest 13.5C on the 25th and lowest 5.4C on the 11th.

November 2024

A dry month with temperatures a little above averages, very dull.

A dry and very dull beginning turning wintry from the middle before turning warm, wet and windy with storm BERT.

Rainfall was 72.3 mm (51%) & [54%] of averages, least since 2011 the 15th driest November in Llansadwrn records since 1928. The wettest day was the 23rd with 21.4 mm the only day in double digits. Unusually 9 days (+5.9) had no precipitation and there were 14 (+6.7) dry days. Rain days 16 were (-6.9); wet days 12 (-5.5); and days with 5 mm, or more 5 (-4.3).

It was a little wetter in Llanfairfechan at Gorwel Heights just exceeding the 100 mm mark with 100.3 mm (76%) & [81%] of averages, leas since 2021. Here the wettest day was on the 23rd with 29.0 mm with the 22nd having 20.7 mm the combined 49.7 mm nearly half of the month's total. There were 16 dry days; 15 rain days; 10 wet days; and 5 days reached 5 mm, or more. Rainfall duration (wet hours) was 92h while in Llansadwrn duration was 94h. At Gorddinog, Llanfairfechan, 94.4 mm was recorded with 37.7 mm falling on the 23rd.

The mean temperature in Llansadwrn was 8.8C (+0.4) & [+0.9], highest since 2022 ranking 10 in station records since 1979.

The mean temperature at Gorwel Heights was 9.6C (+0.3) & [+0.9] highest since 2022.

The mean maximum in Llansadwrn 11.5C (+0.5) & [+1.1] of averages highest since 2022, the highest maximum was 17.2C on the 29th was Föhn-enhanced and exceeded the highest UK official 15.5C on the day recorded at Porthmadog, but several other UK stations reported 18C, or more. Llansadwrn's 17.2C was exceeded by the 17.6C at Gorwel Heights and 17.8C at David Lee's Gorddinog AWS and 18.0C Stevenson Screen. The phenomenon was reported by Derek 'The Weather' on the BBC Wales News weather forecast. It was preceded by the coldest day on the 20th when a 4.4C maximum was recorded.

The mean minimum in Llansadwrn was 6.2C (+0.3) & [+0.7] one day of air frost -0.3C on the 21st, frost for 2.8h. There were 7 days of ground frost, lowest -4.6C also on the 21st. The mean minimum at Gorwel heights was 7.3C with a high minimum of 12.9C on the 30th and a low of 0.6C so no air frost recorded there.

It was a very dull month with 13 sunless days recorded in Llansadwrn and Valley. The 21st was particularly dark with nil sunshine and just 0.44 MJ m ^-2 solar radiation and a maximum 30 W at 1000 GMT and then 14 W m^-2 in the hour between 11 and 12 GMT. RAF Valley recorded only 36.8h [(64%)] of sunshine in the month, lowest since 2015, with 6.5 h on the 26th the most. It was the 11th dullest November on the Anglesey record back to 1931.

With storm BERT undergoing rapid cyclogenisis 949 mb just W of Shannon, Ireland, it was a rough day on the 23rd. The lowest pressure here was 981 mb at 0342 GMT on the 24th. At Gorwel Heights a gust of 60 mph was recorded while Capel Curig reported 81 mph, Gorddinog 72 mph, Valley 62 mph, Mona AF and Caernarfon AP 57 mph, and Llansadwrn 50 mph. Ridge tiles and slates were blown from properties across North Wales. Heavy warm rain led to rapid thaw of mountain snow and swollen mountains streams, Llyn Tegid near Bala overflowed the visitor carpark. Similarly Llyn Ogwen filled and runoff flash flooded the A5 washing debris onto the road in places.