July 2011

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

Mean daily maximum: 19.5
Difference from average: +0.2

Mean daily minimum: 9.3
Difference from average: -1.1

Mean air temperature: 14.4
Difference from average: -0.5

Absolute maximum: 23.7 (4th)

Absolute minimum: 5.4 (14th)

Mean grass minimum: 7.1

Absolute grass minimum: 2.9 (14th)

Number of ground frosts: 0

Number of air frosts: 0

Mean soil temperature at 30cm depth: 17.2

Mean soil temperature at 100cm depth: 15.6

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

Total for the month: 86.6
Difference from average: +35.1

Percentage of the average: 168%

Wettest day: 20.8 (21st)

Number of rain days (>0.25mm): 13

Number of wet days (=> 1mm): 11

3-month total rainfall to 31st July: 167.4
Difference from average: +12.3

6-month rainfall total to 31st July: 257.3
Difference from average: -37.9

12-month rainfall total to 31st July: 681.2
Difference from average: +32.2

Humidity
(Averages for 09:00 hours GMT)

Relative Humidity: 80%

Sunshine
(all averages 1961 – 1990)

Total for the month: 125.7 hours
Difference from average: -29.2

Percentage of the average: 81.2%

Mean daily sunshine: 4.1 hours
Difference from average: -0.9

Sunniest day: 11.2 hours (3rd)

Number of days with no recorded sunshine: 0

Cumulative total sunshine since 1st January: 937.7 hours
Difference from average: +92.8

Wind

The mast is still broken, we hope to replace it soon.

ISSN1350-483

Comments on July 2011
This was the coolest July since 2000, ranking only 61st in 162 years. The mean maximum was only the lowest since 2007 but the mean minimum was the lowest since 1962, ranking 10th lowest since 1900. Rainfall was somewhat above average and sunshine rather below average. All in all, a rather disappointing July!

Professor Tim Burt
Department of Geography
Durham University