December 2005

Temperatures
(all temperatures in degrees Celsius; all averages 1961 – 1990)

Mean daily maximum: 7.3
Difference from average: +1.3

Mean daily minimum: 1.2
Difference from average: +0.1

Mean air temperature: 4.3
Difference from average: +0.4

Absolute maximum: 12.7 (12th)

Absolute minimum: -9 (29th)

Mean grass minimum: 0.0

Absolute grass minimum: -5.5 (28th)

Number of ground frosts: 18

Number of air frosts: 10

Mean soil temperature at 30cm depth: 4.9

Mean soil temperature at 100cm depth: 7.5

Rainfall
(all totals in millimetres; all averages 1961 – 1990)

Total for the month: 34.8
Difference from average: -22.6

Percentage of the average: 61%

Wettest day: 9 (5th)

Number of rain days (>0.25mm): 13

Number of wet days (=> 1mm): 9

3-month total rainfall to 31st December: 182
Difference from average: +10.1

6-month rainfall total to 31st December: 355.7
Difference from average: +9.3

12-month rainfall total to 31st December: 592.1
Difference from average: -56.9

Humidity
(Averages for 09:00 hours GMT)

Relative Humidity: 86%

Sunshine
(all averages 1961 – 1990)

Total for the month: 53.2 hours
Difference from average: +7.6

Percentage of the average: 117%

Mean daily sunshine: 1.7 hours
Difference from average: +0.2

Sunniest day: 5.2 hours (12th)

Number of days with no recorded sunshine: 6

Cumulative total sunshine since 1st January: 1332.1 hours
Difference from average: +2.8

Wind

The mean wind speed: 11.1km/h [6kt]
Difference from average: -4.1km/hr

The highest gust: 68.5km/h [37kt] from 247° at 00:48 GMT on 16th

ISSN1350-483

Comments on December 2005
Like November, December was a mixed month: some very mild days in the middle but extremely cold after Christmas. The absolute minimum of -9°C on the 29th was the coldest day in Durham since 4th March 2001 and the lowest December temperature for a decade. The temperature only reached -0.7°C on the 7th. Overall, December was above average temperature, mainly because daytime temperatures were well above average, night-time temperatures being only marginally so. It ranks 99th warmest in a series of 156 years, but was the coolest this decade. December was a dry month, with only 61% of the normal amount. Sunshine was a little over average, but it was a calm month, with mean wind speed well below average.

Professor Tim Burt
Department of Geography
Durham University