July 2020

Temperatures
(all temperatures in degrees Celsius; all averages 1961 – 2010)

Mean daily maximum: 19.3
Difference from average: -0.8

Mean daily minimum: 11.0
Difference from average: -0.1

Mean air temperature: 15.1
Difference from average: -0.5

Absolute maximum: 30.8 (31st)

Absolute minimum: 7.5 (12th)

Mean grass minimum: 9.2

Absolute grass minimum: 4.4 (20th)

Mean concrete minimum: 10.9

Absolute concrete minimum: 7.3 (20th)

Number of ground frosts: 0

Number of air frosts: 0

Mean soil temperature at 30cm depth:

Mean soil temperature at 100cm depth:

Rainfall
(all totals in millimetres; all averages 1961 – 2010)

Total for the month: 55.6
Difference from average: +0.6

Percentage of the average: 101%

Wettest day: 9.8 (10th)

Number of rain days (>0.2mm): 21

Number of wet days (=>1.0mm): 14

3-month total rainfall to 31st July: 156.2
Difference from average: -15.8

6-month rainfall total to 31st July: 273.8
Difference from average: +72.4

12-month rainfall total to 31st July: 700
Difference from average: +51

Sunshine
(all averages 1961 – 1990)

Total for the month: 129.5 hours
Difference from average: -44.4

Percentage of the average: 74.5%

Mean daily sunshine: 4.2 hours
Difference from average: -1.4

Sunniest day: 10.2 hours (5th)

Number of days with no recorded sunshine: 0

Cumulative sunshine since 1st January: 1078.8
Difference from average: 162.5

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

Average wind speed: 6.2kph

Maximum gust: 80.5kph (15:15, 5th, W)

ISSN1350-483

Comments on July 2020
It took until the 12th before the daily maximum exceeded 20°C and indeed, up until the last day of the month, the highest temperature had been 23.2°C on the 16th. This seems a modest high point, but it does rank in the upper quartile of warmest July days since 1900. 31st July saw the second warmest July day ever at Durham (30.8°C), beaten only by last July’s 32.9°C. This is the fourth highest maximum recorded on any day at Durham since 1900; two days in August 1990 were also warmer.

The rainfall total was almost exactly average for July but the number of rain days (21) was high, the 11th equal highest number for any July since 1850. Not surprisingly, it was a dull month therefore, the dullest July since 2000 and the 23rd dullest July since 1882.

There was a yellow weather warning from the Met Office for strong winds on the 5th. Durham experienced a gust of 80.5kph that afternoon with a very high average wind speed for the day as a whole of 20kph. While other parts of the country experienced heavy rain, Durham had 10 hours of sunshine and only 0.2mm rainfall.

Emeritus Professor Tim Burt
Department of Geography
Durham University