Weather review – December 2014

The weather in December 2014 was a very mixed bag with alternating mild and cold spells before the first significant snowfall of the Winter on the 26th. The all-time highest December temperature record was broken as was the yearly minimum temperature. Precipitation was well below average and winds were slightly stronger than normal.

The maximum temperature in the month was 13.0°C on the 18th at 13:49 and the minimum temperature was -3.1°C on the 30th at 05:42. This was the highest December temperature recorded here, beating the previous best, set on December 26th 2011, by 0.1°C. The minimum temperature on this day (18th) was 10.3°C, recorded at 00:00, the highest December daily minimum ever recorded here. The average temperature for the month was 4.6°C, 0.8°C above the December mean. This was the 11th month in 2014 to record above average temperatures, only August prevented the clean sweep. The minimum temperature of -3.1°C was the coldest here since -3.7°C was recorded on March 14th 2013. On the 26th, the low wind chill of -5.2°C was the lowest recorded in 2014. Despite the varied weather, December had 70.7 hours of sunshine, 12 hours more than 2013, and 9.5 hours above the month average. The average daily maximum temperature was 7.4°C, 1.1°C above the mean, while the average minimum temperature was 2.1°C, 0.8°C above the mean. The average dew point was 3.1°C and the maximum heat index was 13.0°C set at 13:49 on the 18th.

Precipitation was recorded on 24 days totalling 31.2 millimetres. This took the 2014 total to 549.6 millimetres, slightly below the yearly average. On the 5th, a short spell of light drizzle (0.2 millimetres) ended a run of five successive dry days, equalling the longest dry spell recorded here in December. Strangely, this dry spell occurred at exactly the same time last year (November 30th until December 4th). The first snowfall of the autumn / winter season was recorded on the 11th at 08:15. The snow settled in places on the grass but soon turned to rain. 6.0 centimetres of snow fell on the 26th, the most since 23rd March 2013, followed by a further 3.0 centimetres on the 27th, when the snow depth was 9.0 centimetres, the deepest since March 25th 2013. Evapotranspiration for the month was 15.0 millimetres, 0.6 millimetres less than 2013.

Winds were slightly above average with the maximum wind speed being 24.2 mph from 270° (W) on the 22nd at 03:57. The maximum gust speed was 39.1 mph from 270° (W) also on the 22nd at 03:44. The total wind run was 3900.4 miles.

The average barometric pressure in the month was 1016.0 millibars, with the highest being 1041.1 millibars at 20:48 on the 29th and the lowest being 985.8 millibars at 04:29 on the 12th. The highest and the average were both December records. On the 26th, the maximum pressure recorded was 1030.0 millibars at 00:08. This fell to 1004.7 millibars at 22:15 – a drop of 26.3 millibars in a little over 22 hours, enough to be classified as a ‘weather bomb‘.

Weather Underground graph for December 2014