Davis Vantage Vue AWS at Gorwel Heights in Llanfairfechan.

Llansadwrn (Anglesey) Weather:
Monthly and Annual
Summary for 2025

 Logo: Llansadwrn Weather - Melin Llynnon, Ynys Môn



January 2025

Wet and windy with storm Éowyn bringing record high gusts to Ireland, temperatures a little below averages

A wintry beginning with a very mild spell followed by storm Éowyn

Rainfall totalled 129.5 mm ranking as one of the 34 wettest Januaries in Llansadwrn since records began in 1928. Least since 2022 it was (105%) of the decadal average that had seen some very wet Januaries (180.6 mm in 2021), and [125%] of the somewhat drier 1991-2020 period average. The wettest day was on the 5th with 19.2 mm much falling as ice precipitation. There were 6 days with no precipitation (+1.9); 19 dry days (+2.2); 21 rain days (-2.2); 15 wet days (-1.1); and 9 (+1.0) with 5 mm, or more. At Gorwel Heights in Llanfairfechan rainfall of 136.0 mm (119%) & [153%] of averages was least since 2022, here the wettest day was on the 23rd with 30.6 mm while the 5th saw 30.4 mm. Here there were 8 dry days; 23 rain days; 17 wet days; and 7 had 5 mm, or more. Rainfall duration (wet hours) was 131 h at Gorwel heights and 128 h in Llansadwrn.

The mean temperature 5.0C in Llansadwrn (-0.7) & [-0.4[ of averages was lowest since 2021 and the 17th lowest in records since 1979. The mean maximum was 7.3C with the highest maximum 11.9C on the 16th and the lowest 2.0C on the 8th. The mean minimum was 2.6C with the lowest minima -2.2C on the 9th and -1.4C on the 10th resulting in 23.2 hours of frost the only two days of air frost recorded. There were 19 days of ground frost (+2.2) with the lowest -6.2C on the 9th. An air frost of -0.9C was also recorded at Gorwel Heights on the 9th with 6.5h of frost recorded. Here the mean minimum was 3.5C with the highest 10.5C on the 14th . The mean maximum was 8.0C with the highest 13.2C on the 14th and lowest 3.3C on the 8th. The mean 5.8C was (-0.8) & [-0.4] of averages was lowest since 2021.

Gorwel Heights had extreme wind speeds on the 24th for 3 hours between 0120 and 0410 GMT recording a high gust of 76 mph. At 0240 GMT a 10 min (height corrected) mean wind speed of 47 mph force 9 was recorded, likely responsible for blowing over a long length of brick wall. The highest gusts in Llansadwrn were 58 mph at 0220 GMT and 57 mph at 0740 GMT. Between 0220 and 1000 GMT 20 gusts of 50 mph, or more, were recorded. The wind resulted in the removal of several roof slates. This was the windiest spell recorded at the stations since before 2010.

 .

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Monthly data 2025

Llansadwrn (Anglesey): Monthly weather data summary for 2025
Anomaly ~ is based on the 2015-24average.
Anomaly 30-y is based on the 1991-2020 average.
.
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year
Air temperatures (C)
.
Mean max 7.3 7.3
Mean min 2.6 2.6
Mean 5.0 5.0
Anomaly~ -0.7 0.2
Anomaly 30-y -0.4 0.4
High max 11.9 11.9
Date 16 .
Low max 2.0 2.0
Date 8 .
High min 7.9 7.9
Date 8 .
Low min -2.2 -2.2
Date 9 .
Grass min -6.2 -6.2
Date 9 .
.
MSL Pressure at 09 GMT (mb) 1011 1011
Highest 1037 1037
Date 12 .
Lowest 969.5 969.5
Date 27 .
.
Means at 0900 GMT .
Air temperature (C) 4.3 4.3
Dew point (C) 3.3 3.3
RH% 94 94
Soil temperatures (C) .
.
5 cm 3.7 3.7
10 cm 4.1 4.1
20 cm 4.5 4.5
30 cm 5.5 5.5
Anomaly~ -0.5 -6.1
50 cm 6.3 6.3
100 cm 7.5 7.5
Anomaly~ -0.3 -4.4
.
Rainfall (mm) .
.
Rain tot 129.5 129.5
Rain % ave~ 105 10
Rain % 30-y 125 11
Days 0.0 6 6
Days <0.2 10 10
Days >=0.2 21 21
Days >=1.0 15 15
Days >=5.0 9 9
Max fall 19.2 19.2
Date 5 .
Highest rate (mm/h) 25 25
Date 30 .
Average rain per hour (mm) 1.0
.
Evaporation .
.
Piche (mls/ mm) 23.2 23.2
Lysimeter PE (mm) 13.5 13.5
AWS ET calculated 30.0 30.0
.
Weather (days) .
.
Air frost 2 2
Ground fr 19 19
Sl/snow 4 4
Sn lying 1 1
Thunder 0 0
Hail <5 mm 8 8
Hail >=5 mm 0 0
Fog at 09h 0 0
Gales in SE Anglesey 2 2
.
Wind direction at 09h (days) .
.
N 2 2
NE 2 2
E 2 2
SE 6 6
S 2 2
SW 10 10
W 2 2
NW 3 3
Calm 2 2
.
Wind speed mph .
.
Daily mean 5.3 5.3
Highest daily mean 21.5 21.5
Date 24 .
Mean gust 20.7 20.7
Highest gust 58 58
Date 24 .
.
AWS records of rainfall and frost .
.
Wet hours (with 0.2 mm,or more) 128 128
Frost duration (h) 23.2 23.2
.
Cloud cover at 09h. Mean % ERR
.
Global solar radiation (MJ m-2) .
.
Llansadwrn
Sol rad mean 2.25 2.25
Maximum 4.47 4.47
Date 25 .
Minimum 0.84 0.84
Date 21 .
Brightest hour W/sq m 291 291
during hour beginning GMT 12 12
on day 29 .
Sunless days 11 11
.
Sunshine (h) .
[ ~ missing days are derived] .
Valley 55.4 55.4
Average %~ 103 4
Average 30-y 98 4
Sunniest 7.3 7.3
Date 21 .
Sunless days 11 11
.
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 2025
Anomalies based on 30-y [1991-2020] # & 10-y averages (2015-2023) *
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year
Air temperatures (C)
.
Mean max 8.0 8.0
Mean min 3.5 3.5
Mean 5.8 5.8
Anomaly (2015-2024) * -0.8 -5.8
Anomaly [1991-2020] # -0.4 -4.9
High max 13.2 13.2
Date 14 .
Low max 3.3 3.3
Date 8 .
High min 10.5 10.5
Date 14 .
Low min -0.9 -0.9
Date 9 .
.
MSL Pressure at 09 GMT (mb) 1011 1011
.
Highest 1038 1038
Date 12 .
Lowest 969 969
Date 27 .
.
Means at 0900 GMT
Air temperature (C) 5.2 5.2
Dew point (C) 2.3 2.3
RH% 82 82
.
Rainfall (mm)
.
Total 136.0 136.0
% (2015-2024) * 119 11
% [1991-2020] # 153 12
Max fall 30.6 30.6
Date 23 .
Highest rate (mm/h) 43 43
Date 23 .
.
Wet hours (with 0.2 mm, or more) 131 131
Average rain per hour (mm) 1.0 1.0
.
Days <0.2 8 8
Rain >=0.2 23 23
Wet >=1.0 17 17
Days >=5.0 7 7
.
Weather (days) .
.
Air frost 1 1
Frost duration (h) 6.5 6.5
Wind direction at 09h (days) .
.
N 1 1
NE 1 1
E 1 1
SE 7 7
S 3 3
SW 5 5
W 2 2
NW 3 3
Calm 8 8
.
Mean mph 3.9 3.9
Highest daily mean mph 13.2 13.2
Date 24 .
Mean gust 22.0 22.0
Highest gust 76 76
Date 24 .
.
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, final data from the Met Office website. I am grateful to David Lee for use of his data from Gorddinog.


Designed and written by Donald Perkins © 2025

Page first dated 5 February 2025

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