December 2004

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

Mean daily maximum: 8.2
Difference from average: +1.6

Mean daily minimum: 1.7
Difference from average: +0.6

Mean air temperature: 5.0
Difference from average: +1.1

Absolute maximum: 12.7 (23rd)

Absolute minimum: -2.6 (20th)

Mean grass minimum: -0.6

Absolute grass minimum: -7.9 (3rd)

Number of ground frosts: 17

Number of air frosts: 10

Mean soil temperature at 30cm depth: 5.6

Mean soil temperature at 100cm depth: 8.2

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

Total for the month: 8.2
Difference from average: -49.2

Percentage of the average: 14%

Wettest day: 4.6 (28th)

Number of rain days (>0.25mm): 5

Number of wet days (=> 1mm): 2

3-month total rainfall to 31st December: 143
Difference from average: -28.9

6-month rainfall total to 31st December: 383.6
Difference from average: +15.8

12-month rainfall total to 31st December: 726
Difference from average: +77

Humidity
(Averages for 09:00 hours GMT)

Relative Humidity: 83.4%

Sunshine
(all averages 1961 – 1990)

Total for the month: 75.6 hours
Difference from average: +30

Percentage of the average: 166%

Mean daily sunshine: 2.4 hours
Difference from average: +0.9

Sunniest day: 6 hours (2nd)

Number of days with no recorded sunshine: 4

Cumulative total sunshine since 1st January: 1189 hours
Difference from average: -140

Wind

The mean wind speed: 15km/h [8.1kt]
Difference from average: 0km/hr

The highest gust: 101.9km/h [55kt] from 253° at 11.51 GMT on 23nd

ISSN1350-483

Comments on December 2004
December was another warm month, not quite as extreme as November but still ranking 124th highest in a series of 155. Daily maxima were in particular well above average. This is reflected in a sunny month, a good deal more sunny than November in fact. It was also a very dry month: whilst there must be some doubt about a total as low as 8.2mm, only 17 mm was recorded at Ferryhill, so maybe the total is reliable. That being so, it was the 3rd driest December since 1852, only 1871 and 1852 being drier.

Professor Tim Burt
Department of Geography
Durham University