August 2019

Temperatures
(all temperatures in degrees Celsius; all averages 1981 – 2010)

Mean daily maximum: 20.5
Difference from average: +0.8

Mean daily minimum: 12.5
Difference from average: +1.5

Mean air temperature: 16.5
Difference from average: +1.1

Absolute maximum: 28.1 (25th)

Absolute minimum: 9.1 (21st)

Mean grass minimum: 10.6

Absolute grass minimum: 6.3 (21st)

Mean concrete minimum: 12.2

Absolute concrete minimum: 9.2 (21st)

Number of ground frosts: 0

Number of air frosts: 0

Mean soil temperature at 30cm depth: 17.7

Mean soil temperature at 100cm depth: 17.6

Rainfall
(all totals in millimetres; all averages 1981 – 2010)

Total for the month: 81.2
Difference from average: +19.8

Percentage of the average: 132%

Wettest day: 17.4 (8th)

Number of rain days (>0.2mm): 20

Number of wet days (=>1.0mm): 12

3-month total rainfall to 31st August: 261.4
Difference from average: +89.4

6-month rainfall total to 31st August: 379.8
Difference from average: +33.6

12-month rainfall total to 31st August: 625.6
Difference from average: -23.4

Sunshine
(all averages 1981 – 2010)

Total for the month: 115.2 hours
Difference from average: -42.3

Percentage of the average: 73%

Mean daily sunshine: 3.7 hours
Difference from average: -1.4

Sunniest day: 9.3 hours (26th)

Number of days with no recorded sunshine: 2

Cumulative total sunshine since 1st January: 935.8 hours
Difference from average: -103.4

Wind
(all data from West Building roof, Lower Mountjoy)

Average wind speed: 5.5kph

Maximum gust: 59.5kph (13:45, 18th, W)

ISSN1350-483

Comments on August 2019
This was the 9th warmest August at Durham since 1850 with the equal 2nd highest mean minimum and the equal 18th highest mean maximum since 1900. Once again night-time temperatures helped to raise the overall mean, suggesting better summer weather than it often felt during the day. There were four hot days towards the end of the month, but 17 others where the maximum remained below 20°C; the maximum of only 15.7 on 11th was particularly disappointing. Rainfall was a little above average, wetter than July but not as wet as June. It was a dull August, not as bad as the previous two Augusts but nevertheless the 23rd lowest total for any August since 1882.

It was the 7th equal warmest summer on record at Durham since 1850 (15.7°C), exactly the same as last year; 2003 holds the record at 16.2°C. It was the 15th wettest summer (261.4mm) since 1850, the wettest since 2012. It was also the 6th dullest summer since 1882 (351.4 hours), although both 2012 and 2017 were worse; the record holder is 1912 with a miserable 223 hours. Spring was sunnier than summer this year. This is not that rare in fact: 37 years since 1882 have had a sunnier spring than summer at Durham. Using the Davis index of summer weather, 2019 was the equal 34th worst summer at Durham since 1900; by contrast summer 2018 ranks 91st in a list of 120 years. This poor result in 2019 reflects high rainfall and lack of sunshine rather than low temperatures.

Emeritus Professor Tim Burt
Department of Geography
Durham University