Monthly summary December 2010

December 2010 was the coldest December that I have recorded and broke many other records. The mean temperature was 5.2°C below the long-term average. There was a record of 25 days with air frost in the month totaling a substantial 424 hours of sub-zero temperatures. There were ten days when the thermometer did not struggle into a positive figure. The extreme low of -11.7°C in the early hours of the 24th was the coldest December night since 1999 and the second coldest on record. It was the driest December since 2001 giving a total of 29.3mm, which was only 32% of the long-term average. Snow fell on a total of eight days and we endured ten days of fog.

The year 2010 was the coldest year since 1987 being 1.1°C below the long-term average and produced a record 32 days of snowfall. The total rainfall of 672mm was just 79% (175mm below) of the long-term average. It was the third driest year after 1997 (671mm) and 1996 (594mm).

Monthly summary December 2009

December began where November finished, with disturbed windy and wet weather. With wind from a southerly quarter from 1st to the 9th, temperatures were above average accompanied by heavy rainfall. As pressure rose and winds swung into a northerly quarter, temperatures dropped and air frost occurred. However, worse was to come as snow fell on the 16th, 17th, 19th and 21st. With strong winds the wind-chill factor was significant for several days dropping to -8°C on the 18th. A snow covering at 0900 of at least 50% was evident from the 20th to the 24th. Rain showers then fell on very cold ground producing sheet ice that covered everything and was extremely dangerous to pedestrians and drivers alike.

With a mean temperature of 2.26°C it was the third coldest December I have recorded, equal to 2001, but less cold than 1996 (2.18°C) and 1995 (1.75°C) and 2°C below the long-term average. It was the wettest December since 2002 with a total of 107.9mm which is 120% of the long-term average. Although the Spring months show a rising trend in temperatures, December is quite the opposite with the frequency and severity of air frosts increasing significantly.

The mean temperature for the year was almost identical to the long-term average of 9.6°C. It is of interest that the average for my records in the 1980’s is 8.9°C. The annual rainfall of 885mm was 105% of the long-term average.