SUMMARY OF THE METEOROLOGICAL READINGS AT DURHAM UNIVERSITY OBSERVATORY
Temperatures (all temperatures in degrees Celsuis; all averages 1991-2020)
Mean daily maximum: 20.7 Difference from average: +2.7
Mean daily minimum: 10.4 Difference from average: +1.1
Mean air temperature: 15.5 Difference from average: +1.8
Absolute maximum: 27.3 (12th)
Absolute minimum: 3.0 (4th)
Mean grass minimum: 9.0 Difference from average: +1.4
Absolute grass minimum: 1.0 (4th)
Mean concrete minimum: 11.1
Absolute concrete minimum: 4.5 (3rd, 4th)
Number of ground frosts: 0 Difference from average: 0
Number of air frosts: 0 Difference from average:
Mean soil temperature at 300 mm depth:
Mean soil temperature at 1000 mm depth:
Rainfall (all totals in millimetres; all averages 1991-2020)
Total for the month: 50.4 Difference from average: -10.8
Percentage of the average: 82%
Wettest day: 19.6 (18th)
Number of rain days (>0.1 mm): 10 Difference from average: -5
Number of wet days (=>1.0 mm): 6
3-month total rainfall to June 30th 2023: 128.2 Difference from average: -28.7
6-month total rainfall to June 30th 2023: 237.2 Difference from average: -59.3
12-month total rainfall to June 30th 2023: 652.8 Difference from average: -28.2
Sunshine (all totals in hours; all averages 1991-2020)
Total for the month: 232.2 Difference from average: +67.8
Percentage of the average: 142%
Mean daily sunshine: 7.7 Difference from average: +2.3
Sunniest day: 10.7 (15th)
Number of days with no recorded sunshine: 0
Note that the monthly sunshine total is now calculated from the UKMO E&NE regional total. Daily sunshine totals quoted here and in the data summary are uncorrected.
Wind (kph; all data from the West Building roof, Lower Mountjoy campus)
Average wind speed: 5.1
Maximum gust: 43.5 (26th, WSW, 12:15)
Comments on June 2023
The mean air temperature for June 2023 is the 4th highest on record since 1844, exceeded only in 1940 (15.7 °C), 1858 (15.8 °C) and 1846 (17.5 °C). In the extended Eglise series, which goes back to 1784, June 2023 ranks 7th; the additional warmer Junes are 1818, 1822 and 1826. It is still not clear why hot Junes have been largely absent in the last 150 years and yet were much more common before that. Whilst 1846 is very early in the Durham record, we can be confident about its mean air temperature: June 1846 remains the hottest June in the Central England Temperature record with a mean air temperature of 18.2 °C. Since June 2022 and June 2021 were also very warm, perhaps we are reverting to June weather last seen in the second quarter of the 19th Century?
The mean maximum temperature for June 2023 is the 3rd highest on record at Durham, surpassed only in 1940 (22.3 °C) and 1846 (22.6 °C). The mean minimum temperature is the equal 5th highest since 1844. The absolute maximum of 27.3 °C on the 12th is the 28th warmest June day since 1844 and the warmest since 2017 (n=5336). After some cooler days at the start of the month, every day except 2 saw a maximum of at least 20 °C; the total of 19 days is the same as in 1970 and only exceeded in 1846 (21) and 1940 (23). For the number of days with a maximum of at least 25 °C, 2023 is one of 10 Junes to see 4 days over this threshold; 1976 had 7, 1940 had 8 and 1846 had 10.
Apart from two days recording 0.2 mm (6th and 17th June), the dry spell lasted from 19th May to 18th June. It ended in spectacular style with a daily total of 19.6 mm on the 18th, which included two consecutive hourly totals of 10 mm and 5.2 mm. Although my record of hourly rainfall for Durham from 1997 is not complete (about 7% of data is missing), the hourly total of 10 mm ranks 22nd in a list of over 200,000 hours. Had it not been for those two days with 0.2 mm totals, the 30-day dry spell would have been exceptional, the 3rd longest on record. All three long-period rainfall totals are now below average.
This was the 7th sunniest June on record, based on a prediction using Met Office E&NE regional data. The poor exposure of the solarimeter in the summer months is shown by the fact that the estimated amount of bright sunshine was just 155.1 hours whereas as the estimated total is 232 hours.
Emeritus Professor Tim Burt
Department of Geography