December 2007

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

Mean daily maximum: 6.7
Difference from average: +0.1

Mean daily minimum: 1.1
Difference from average: 0.0

Mean air temperature: 3.9
Difference from average: 0.0

Absolute maximum: 13.6 (4th)

Absolute minimum: -3.4 (17th)

Mean grass minimum: -0.6

Absolute grass minimum: -7.3 (17th)

Number of ground frosts: 20

Number of air frosts: 13

Mean soil temperature at 30cm depth: 5.1

Mean soil temperature at 100cm depth: 7.9

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

Total for the month: 51.2
Difference from average: -6.2

Percentage of the average: 89%

Wettest day: 15.4 (9th)

Number of rain days (>0.25mm): 12

Number of wet days (=> 1mm): 10

3-month total rainfall to 31st December: 123.2
Difference from average: -48.8

6-month rainfall total to 31st December: 305.2
Difference from average: -41

12-month rainfall total to 331st December: 617.6
Difference from average: -31.4

Humidity
(Averages for 09:00 hours GMT)

Relative Humidity: 89%

Sunshine
(all averages 1961 – 1990)

Total for the month: 48 hours
Difference from average: +2.4

Percentage of the average: 105%

Mean daily sunshine: 3.6 hours
Difference from average: 0.0

Sunniest day: 5.8 hours (6th)

Number of days with no recorded sunshine: 12

Cumulative total sunshine since 1st January: 1305 hours
Difference from average: -24.2

Wind

The mean wind speed: 14.6km/h [7.9kt]
Difference from average: -0.6km/hr

The highest gust: 87km/h [47kt] from 195° at 20:51 GMT on 3rd

ISSN1350-483

Comments on December 2007
Temperatures were exactly average for December, some mild days at the beginning and end of the month balancing some very cold days in the middle, notably on the 14th when a maximum of only -0.6°C was recorded. Sunshine was just a little above average, with rainfall and wind speed just a little below. There was the highest number of ground frosts since 2001 and the most days without sunshine since 2002.

Professor Tim Burt
Department of Geography
Durham University