A brief summary of Durham’s climate
Over the current standard 30 year average period, 1991-2020, the mean temperature at the Durham Observatory site was 9.4 °C (mean daily maximum 13.2 °C, mean daily minimum 5.7 °C). January is the coldest months of the year on average (mean temperature 4.1 °C), while July is the warmest (mean temperature 15.8 °C). Since continuous records of both daily maximum and minimum temperature commenced in August 1843, the coldest night was 8 February 1895, when the minimum temperature fell to -18.0 °C. Within the last 50 years, the coldest night was 11 January 1982, when the temperature reached -16.1 °C. The hottest day on the record to date has been 25 July 2019, when the maximum temperature of 32.9 °C was recorded, closely followed by 32.5 °C on 3 August 1990.
The annual average precipitation over the 30 years 1991-2020 was 680 mm, falling on an average of 196 days per year. The driest period of the year is late winter to early spring (March is the driest month, with 41 mm on average) and the wettest period is autumn (November averages 73 mm), but with wide variations from year to year. The wettest day on record (since the start of homogeneous rainfall records in 1868) was 11 September 1976, when 87.8 mm fell in the 24 hours commencing 0900 GMT. The wettest day of the 21st century to date has been 24 September 2012, when 57.4 mm fell. In the monthly rainfall record since 1868, the wettest month (July 1888) received 210 mm and the wettest year (2012) 1018 mm. No calendar month has ever remained completely dry, the driest months since 1868 being March 1953 (1.3 mm) and June 1925 (1.7 mm), and more recently April 2020 with 3.8 mm. The driest calendar year was in 1989 (416 mm, just 61 per cent of the current average). Snow can be expected to fall on around 14 days in a typical year, with the ground snow-covered on about 18 mornings. The greatest known snow depth during the period 1961-99 was 43 cm in February 1963.
The average annual sunshine duration is 1473 hours, about 33 per cent of the possible duration of daylight at this latitude. Since sunshine records commenced in May 1880, the dullest month on record was January 1996 with just 7.6 hours of bright sunshine during the month (an average of less than 15 minutes per day); contrast this with June 1940, the sunniest month on record, when the Sun shone for 297 hours, an average just short of 10 hours daily.
Over the period of available record (1843-1960), the annual average barometric pressure at mean sea level at 0900 GMT was 1013.2 hPa (millibars). The lowest observed barometric pressure occurred on 8 December 1886, when the mean sea level value at 2100 GMT was 936.2 hPa; the highest observed barometric pressure occurred on 23 January 1907, when the mean sea level value at 0900 GMT was close to 1051 hPa.
Burt, Stephen and Burt, Tim, 2022. Durham Weather and Climate since 1841. Oxford University Press, 580 pp.