April 2010
Temperatures
(all temperatures in degrees Celsius; all averages 1961 – 1990)
Mean daily maximum: 13.5
Difference from average: +2.5
Mean daily minimum: 3.6
Difference from average: +0.5
Mean air temperature: 8.6
Difference from average: +1.6
Absolute maximum: 19.8 (28th)
Absolute minimum: -1.8 (2nd)
Mean grass minimum: 0.8
Absolute grass minimum: -5.0 (2nd)
Number of ground frosts: 16
Number of air frosts: 3
Mean soil temperature at 30cm depth: 9.2
Mean soil temperature at 100cm depth: 8.6
Rainfall
(all totals in millimetres; all averages 1961 – 1990)
Total for the month: 12.4
Difference from average: -35.1
Percentage of the average: 26%
Wettest day: 3.8 (2nd)
Number of rain days (>0.25mm): 7
Number of wet days (=> 1mm): 4
3-month total rainfall to 30th April: 148.2
Difference from average: +8.0
6-month rainfall total to 30th April: 445.4
Difference from average: +126.7
12-month rainfall total to 30th April: 824.2
Difference from average: +175.2
Humidity
(Averages for 09:00 hours GMT)
Relative Humidity: 72%
Sunshine
(all averages 1961 – 1990)
Total for the month: 138.5 hours
Difference from average: +5.3
Percentage of the average: 104%
Mean daily sunshine: 4.6 hours
Difference from average: +0.2
Sunniest day: 11.5 hours (1st)
Number of days with no recorded sunshine: 0
Cumulative total sunshine since 1st January: 380.8 hours
Difference from average: +23
Wind
The anemometer remains problematic, no summary results can be provided.
ISSN1350-483
Comments on April 2010
April was a warm month with daytime temperatures in particular well above average. It was the = 10th highest mean maximum in 111 years of record and the = 15th highest mean air temperature for April since 1850. Nevertheless, the 12-month average was again just below 9°C (8.97°C).
It was the 11th driest April since 1850. [Only 2.2mm in 1938!] It was the driest month since February 2008.
Curiously, for the second month in a row, the sunniest day was the 1st!
Professor Tim Burt
Department of Geography
Durham University