June 2012

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

Mean daily maximum: 16.1
Difference from average: -1.4

Mean daily minimum: 8.3
Difference from average: -0.3

Mean air temperature: 12.2
Difference from average: -0.8

Absolute maximum: 21.5 (27th)

Absolute minimum: 3.5 (4th)

Mean grass minimum: 6.8

Absolute grass minimum: 1.2 (3rd)

Number of ground frosts: 0

Number of air frosts: 0

Mean soil temperature at 30cm depth: 14.4

Mean soil temperature at 100cm depth: 12.6

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

Total for the month: 138.6
Difference from average: +86.8

Percentage of the average: 267%

Wettest day: 27.4 (28th)

Number of rain days (>0.25mm): 22

Number of wet days (=> 1mm): 16

3-month total rainfall to 30th June: 337.8
Difference from average: +165.8

6-month rainfall total to 30th June: 401.6
Difference from average: +55.4

12-month rainfall total to 30th June: 748.0
Difference from average: +99.0

Humidity
(Averages for 09:00 hours GMT)

Relative Humidity: 84%

Sunshine
(all averages 1961 – 1990)

Total for the month: 72.1 hours
Difference from average: -91.6

Percentage of the average: 44%

Mean daily sunshine: 2.4 hours
Difference from average: -3.1

Sunniest day: 10.8 hours (20th)

Number of days with no recorded sunshine: 0

Cumulative total sunshine since 1st January: 660.4 hours
Difference from average: -29.7

ISSN1350-483

Comments on June 2012
June was an extremely poor month in all respects!

Daytime temperatures were particularly disappointing. The mean maximum temperature was well below normal, the lowest since 1997. Night-time temperatures were only a little less than usual, but still the lowest since 1999. The resulting mean air temperature was therefore well below average, the lowest since 1991 and 32nd equal lowest since 1850, easily in the lowest quartile. The absolute maximum was the lowest since 2002.

June was another very wet month, the third above average in a row; like April it was exceptional. This was the third wettest June on record at Durham since 1850, exceeded only by 1997 (177.4mm) and 1980 (191.4mm). The three-month total (April to June inclusive) is the 12th highest total for any three months since 1850 (n = 1948) and the highest since May – July 1980. There were daily totals above 20mm on the 8th (21.2mm), 15th (20.6mm) and 28th (27.4mm). A very intense storm on the relatively warm afternoon of the 28th produced hourly totals of 13.6mm (1600 – 1659) and 5mm (1700 – 1759). Probably the storm lasted no longer than about 30 minutes; we have no means of tracking anything other than hourly totals, but the estimated intensity is certainly “noteworthy” (Salter, 1921).

This was easily the dullest June on record at Durham since 1882, well below the previous worst, 1987. There were 3 hours less bright sunshine per day than in a normal June, and only the 20th saw more than 10 hours bright sunshine.

Reference: M de C. S. Salter. (1921). The rainfall of the British Isles. University of London Press, London.

Professor Tim Burt
Department of Geography
Durham University