June 2020

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

Mean daily maximum: 18.2
Difference from average: +0.6

Mean daily minimum: 10.1
Difference from average: +1.1

Mean air temperature: 14.2
Difference from average: +0.9

Absolute maximum: 27.1 (24th)

Absolute minimum: 4.1 (9th)

Mean grass minimum: 8.8

Absolute grass minimum: 0.8 (9th)

Mean concrete minimum: 10.6

Absolute concrete minimum: 4.4 (9th)

Number of ground frosts: 0

Number of air frosts: 0

Mean soil temperature at 30cm depth: 15.3

Mean soil temperature at 100cm depth: 13.4

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

Total for the month: 82.6
Difference from average: +28.2

Percentage of the average: 152%

Wettest day: 33.8 (11th)

Number of rain days (>0.2mm): 19

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

3-month total rainfall to 30th June: 104.4
Difference from average: -67.6

6-month rainfall total to 30th June: 251.62
Difference from average: -95

12-month rainfall total to 30th June: 714.6
Difference from average: +65.6

Sunshine
(all averages 1981 – 2010)

Total for the month: 156.1 hours
Difference from average: -6.2

Percentage of the average: 96%

Mean daily sunshine: 5.2 hours
Difference from average: -0.2

Sunniest day: 10.6 hours (25th)

Number of days with no recorded sunshine: 2

Cumulative sunshine since 1st January: 949.3
Difference from average: +206.9

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

Average wind speed: 6.6kph

Maximum gust: 67.6kph (18:30, 28th, SW)

ISSN1350-483

Comments on June 2020
This is a revised report, after correcting observations on 25th related to a visit by an engineer. Most importantly, the near-record high temperature has been downgraded. The apparent total of 10.4mm has been deleted since this related to checking the rain gauge.

The start of June saw the end of the long spell of anticyclonic weather; cyclonic systems dominated the month, with just a brief heatwave which peaked on the 24th.

This was the equal 20th warmest June since 1850. Days were relatively cool, only the 40th equal highest mean maximum, despite three days above 25°C. Nights were mild with the 5th equal highest mean minimum, including the 12th highest June minimum on the 23rd (15.5°C).

It was the 25th wettest June since 1850 with the 16th equal highest number of rain days (19), four more than in April and May combined. The total of 33.8mm on the 11th is the 6th wettest June day since 1850. The rain lasted for 18 hours with three hours having more than 4mm per hour accumulations. Sunshine was just below average, the first such month in 2020, with cumulative sunshine since the start of the year remaining well above average.

A further note on sunshine records at Durham since 2000
Further scrutiny of the corrected sunshine records suggested that the estimates using Cockle Park were too high from around 2008. Accordingly, a new set of estimates has been produced for the months April to October using the Met Office monthly sunshine figures for the East and North-East Region. As noted in the May report, daily data have not been adjusted. Where infills of daily data from Copley have been used in the past, it is clear that these are significantly higher than anything recorded in the extended summer by the automatic weather station at the Observatory. It is hoped the sunshine recorder can be relocated in due course.

Met Office National Climate Information website:
https://www.metoffice.gov.uk/research/climate/maps-and-data/uk-and-regional-series

Emeritus Professor Tim Burt
Department of Geography
Durham University