January 2021

Temperatures (all temperatures in degrees Celsuis; all averages 1991-2020)

Mean daily maximum: 5.1 Difference from average: -1.8

Mean daily minimum: -0.4 Difference from average: -1.7

Mean air temperature: 2.3 Difference from average: -1.8

Absolute maximum: 10.0 (19^th)

Absolute minimum: -4.7 (9^th)

Mean grass minimum: -1.7

Absolute grass minimum: -7.7 (9^th)

Mean concrete minimum: -1.2

Absolute concrete minimum: -4.6 (24^th)

Number of ground frosts: 23

Number of air frosts: 16

Mean soil temperature at 300 mm depth: 3.3

Mean soil temperature at 1000 mm depth: 5.7

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

Total for the month: 137.2 Difference from average: +84.2

Percentage of the average: 259%

Wettest day: 18.6 (20^th)

Number of rain days (>0.1 mm): 22

Number of wet days (=>1.0 mm): 18

3-month total rainfall to 31^st January 2021: 277.2 Difference from average: +105.2

6-month total rainfall to 31^st January 2021: 541.6 Difference from average: +195.4

12-month total rainfall to 31^st January 2021: 809.4 Difference from average: +160.4

Sunshine (all totals in hours; all averages 1981-2010)

Total for the month: 60.6 Difference from average: -1.3

Percentage of the average: 98%

Mean daily sunshine: 2.0 Difference from average: 0

Sunniest day: 7.3 (9^th)

Number of days with no recorded sunshine: 2

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: 5.0

Maximum gust: 59.5 (21^st, 04;15, WNW)

Comments on January 2021

Apart from a 5-day dry spell (22^nd-26^th), the high frequency of rain days continued from December throughout January; altogether there were 22 rain days and 18 wet days. The wettest day was the 20th, the third day to be affected by Storm Christoph which provided 38 mm in total. This is the second wettest January on record at Durham since 1850; only January 1948 has been wetter (192.1 mm). It is already the 8^th wettest winter on record!

In terms of temperature. This was quite the opposite to January 2020, which was the 5^th warmest January on record. January 2021 was the 34^th equal coldest January since 1850, the coldest January since 2010. It was the 54^th equal lowest mean maximum and the 44^th equal lowest mean minimum. There were no ‘ice days’ , the lowest maximum being 1.1 °C on the 8^th.

Despite all the rain, the number of sunshine hours was just about average.

Emeritus Professor Tim Burt

Department of Geography

Durham University