August 2012

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

Mean daily maximum: 19.9
Difference from average: +0.8

Mean daily minimum: 10.7
Difference from average: +0.3

Mean air temperature: 15.3
Difference from average: +0.6

Absolute maximum: 23.5 (14th)

Absolute minimum: 1.9 (31st)

Mean grass minimum: 8.9

Absolute grass minimum: 0.5 (31st)

Number of ground frosts: 0

Number of air frosts: 0

Mean soil temperature at 30cm depth: 17.0

Mean soil temperature at 100cm depth: 15.4

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

Total for the month: 103.8
Difference from average: +36.7

Percentage of the average: 154%

Wettest day: 23.8 (15th)

Number of rain days (>0.25mm): 18

Number of wet days (=> 1mm): 12

3-month total rainfall to 31st August: 340.0
Difference from average: +168.0

6-month rainfall total to 31st August: 554.8
Difference from average: +208.0

12-month rainfall total to 31st August: 758.6
Difference from average: +109.6

Humidity
(Averages for 09:00 hours GMT)

Relative Humidity: 84%

Sunshine
(all averages 1961 – 1990)

Total for the month: 107.1 hours
Difference from average: -48.4

Percentage of the average: 69%

Mean daily sunshine: 3.5 hours
Difference from average: -1.5

Sunniest day: 7.6 hours (28th)

Number of days with no recorded sunshine: 1

Cumulative total sunshine since 1st January: 856.8 hours
Difference from average: -143.7

ISSN1350-483

Comments on August 2012
August was above average temperature but not greatly so, ranking 121st in 163 years. Days were rather more above average than nights: 17 of the first 21 days exceeded 20°C but the maximum was only 23.5°C (14th). Thereafter it was cooler and the maximum on the 30th was only 13.8°C. The summer as a whole was 0.2°C below average, ranking only 72nd out of 163.

Rainfall was well above average, 136th wettest since 1850. This simply added to an already exceptionally wet late spring and summer: Durham has just experienced the 37th wettest 5-month period since 1850 (n=1947); there is only a 1.9% chance of such a wet period. For all years since 1850, there was easily the biggest contrast between rainfall total in the first three months (January – March) and the rainfall total in the next five months (April – August); the ratio in 2012 was 8.5, much larger than 5.9 in 1867.

August was sunnier than June or July but May and even March were both sunnier. It has been a very dull summer therefore. This was the second dullest summer at Durham since records began in 1882 (268.5 hours) but still considerably sunnier than 1912 when the total was only 223 hours. Only 6 days in August had more than 6 hours sunshine.

Professor Tim Burt
Department of Geography
Durham University