December 2014

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

Mean daily maximum: 7.7
Difference from average: +1.1

Mean daily minimum: 2.1
Difference from average: +1.1

Mean air temperature: 4.9
Difference from average: +1.0

Absolute maximum: 13.7 (18th)

Absolute minimum: -2.6 (4th)

Mean grass minimum: 0.0

Absolute grass minimum: -5.2 (4th)

Number of ground frosts: 16

Number of air frosts: 10

Mean soil temperature at 30cm depth: 6.4

Mean soil temperature at 100cm depth: 8.8

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

Total for the month: 27.0
Difference from average: -30.5

Percentage of the average: 47%

Wettest day: 5.0 (23rd)

Number of rain days (>0.25mm): 12

Number of wet days (=> 1mm): 7

3-month total rainfall to 31st December: 131.6
Difference from average: -40.4

6-month rainfall total to 31st December: 281.4
Difference from average: -64.8

12-month rainfall total to 31st December: 633.0
Difference from average: -16.0

Humidity
(averages for 09:00 hours GMT)

Relative Humidity: 82%

Sunshine
(all averages 1961 – 1990)

Total for the month: 96 hours
Difference from average: +50.4

Percentage of the average: 210%

Mean daily sunshine: 3.1 hours
Difference from average: +1.6

Sunniest day: 6.9 hours

Number of days with no recorded sunshine:

Cumulative total sunshine since 1st January: 1290.1 hours
Difference from average: -39.1

ISSN1350-483

Comments on December 2014
December was another month with above-average temperature, although not nearly so mild as December 2013. Nevertheless it was the 39th equal warmest in 165 years. Both mean maximum and mean minimum were well above average.

Only August has been below average temperature in 2014 and given the December figure, 2014 has been the warmest year in Durham since records began in 1850. Indeed, if the 2014 average temperature (10.07°C) is expressed to two decimal places, this is the first time that the annual average has exceeded 10°C at Durham; the previous records holders (2004, 2011) both averaged 9.96°C. Of the ten warmest years at Durham, eight have been since 2000; 1990 and 1949 are the only exceptions. The mean maximum temperature (13.5°C) is the 1900 whilst the mean minimum temperature (6.6°C)  is the highest on record. There were only 65 ground frosts, the second lowest total on record.

Rainfall was below average for the third month in four and all longer-period totals are now below average. Following two very wet years, 2014 was the driest since the very dry year of 2011.

There were more than twice as many hours of bright sunshine than would be expected in December but nevertheless the annual total fell below average. This was the sunniest December at Durham since 1882, easily beating the previous record: 79 hours in 1886.

It is possible that Durham was the sunniest location in the country in December, although this is yet to be verified.

Professor Tim Burt
Department of Geography
Durham University