May 2021 was cooler than average (9.67°C versus an average of 11.55), wetter than average (88.00 mm versus an average total of 38.84) and calmer than average (a wind run of 2493 miles versus an average of 2649).
The cold, dry weather of April was replaced by a cold, wet May. The maximum temperature in the month was 21.7°C at 17:47 on the last day of the month. The minimum temperature was -0.1°C at 05:44 on the 6th. The average temperature in the month was 9.7°C, the lowest monthly average for May here. The average daily high temperature was 14.4°C (1.5°C below the mean) and the average daily low temperature was 5.4°C, (1.6°C below the mean). This was the lowest May daily average ever recorded here.
The warmest day was the 29th with an average temperature of 15.3°C, while the coldest day was the 6th with an average temperature of 4.7°C. There was one frost day in the month The sunniest day was the 5th with 10.35 hours of sun. There were 191.1 hours of sun in the month, a low for May.
Rainfall in the month was 88.0 millimetres recorded on 22 days. The yearly total was 275.8 millimetres, 132% of the average for the end of May. The wettest day was the 8th with 14.4 millimetres. The highest rain rate of 87.2 millimetres per hour was recorded at 18:20 on the 26th, the highest of the year so far. There was no snow recorded in the month.
The highest barometric pressure of 1029.1 millibars was at 09:10 on the 30th. The lowest pressure was 985.1 millibars at 01:34 on the 4th. The average pressure in the month was 1007.7 millibars, a low for May. The highest humidity was 99% and the monthly average humidity was 82%. The lowest humidity was 43% at 15:02 on the 2nd.
Wind speeds were lower than average, with the highest wind gust speed of 29 mph being recorded at 17:39 on the 3rd. The maximum wind speed was 14 mph at 13:49 on the 21st. The wind run was 2493.0 miles, 384 mph below the average for the month. The average gust speed in the month was 5.1 mph, and the average wind speed was 3.36 mph. The predominant direction was west north westerly (207°).
The maximum high solar radiation recorded at 12:16 on the 12th was 1194 w/m², the highest of 2021 so far.. The average solar radiation for the month was 175 w/m². The highest U.V. Index was 5.5 recorded at 13:00 on the 31st, the highest since 5.6 was recorded on August 5th 2020.