December 2021 was warmer than average (5.61°C versus an average of 4.81), wetter than average (73.60 mm versus an average total of 55.05) and calmer than average (a wind run of 2953 miles versus an average of 3295).
Although December’s weather was fairly typical, an exceptionally mild end to the month saw the second highest temperature ever recorded on New Year’s Eve (31st). This was only 0.5°C short of the highest ever December temperarure, recorded on December 19th 2015. The highest temperature in the month was the 14.3°C recorded at 13:04 on the 31st. The lowest temperature in the month was -0.7°C recorded at 08:00 on the 22nd. The monthly average temperature was 5.6°C, 0.8°C below the mean. The average daily high was 7.8°C, with the average daily low being 3.4°C.
The warmest day was the 30th with an average temperature of 13.0°C, while the sunniest day was the 2nd with 2.6 hours. The coldest day was the 22nd with an average of 1.3°C. There was a total of 3.23 hours of sunshine in the month. There were four frost days in the month.
Rainfall in the month totalled 73.6 millimetres, recorded on 27 days. There was also 10 millimetres of snow, recorded on one day. The wettest day was the 8th when 13.4 millimetres fell. The yearly total was 605.2 millimetres, well above the average of 543.6 millimetres. The highest rain rate was 34.2 millimetres per hour recorded at 15:10 on the 7th.
The highest barometric pressure of 1032.9 millibars was 1041.5, equalling the best for 2021, recorded at 10:27 on the 17th.The lowest pressure was 978.2 millibars at 23:03 on the 26th. The average pressure in the month was 1009.8 millibars. The highest humidity was 100% and the monthly average humidity was 92%. The lowest humidity was 63% at 13:01 on the 2nd.
Wind speeds were lower than average, with the highest wind gust speed of 32 mph being recorded at 00:12 on the 8th. The maximum wind speed was 16 mph at 15:05 on the 8th. The wind run was 2953.4 miles, 790.6 miles below the average for the month. The average gust speed in the month was 5.8 mph, and the average wind speed was 4.0 mph. The predominant direction was south south-westerly (203°).
The maximum high solar radiation recorded at 11:45 on the 4th was 327 w/m². The average solar radiation for the month was 16 w/m². No U.V. Index was recorded.