December 2025
SUMMARY OF THE METEOROLOGICAL READINGS AT DURHAM UNIVERSITY OBSERVATORY
December 2025
Temperatures (all temperatures in degrees Celsius; all averages 1991-2020)
Mean daily maximum: 8.6 Difference from average: +1.5
Mean daily minimum: 3.9 Difference from average: +2.6
Mean air temperature: 6.3 Difference from average: +2.1
Absolute maximum: 14.6 (9th)
Absolute minimum: -2.6 (31st)
Mean grass minimum: 2.1 Difference from average: +2.4
Absolute grass minimum: -6.2 (31st)
Mean concrete minimum: 3.0
Absolute concrete minimum: -3.7 (31st)
Number of ground frosts: 9 Difference from average: -7
Number of air frosts: 2 Difference from average: -9
Mean soil temperature at 300 mm depth: 7.4
Mean soil temperature at 1000 mm depth: 8.6
Rainfall (all totals in millimetres; all averages 1991-2020)
Total for the month: 64.0 Difference from average: +2.8
Percentage of the average: 105
Wettest day: 10.2 (15th)
Number of rain days (>0.1 mm): 18 Difference from average: -1
Number of wet days (=>1.0 mm): 14 Difference from average: +2
3-month total rainfall to 31st December 2025: 246.8 Difference from average: +47.1
6-month total rainfall to 31st December 2025: 401.8 Difference from average: +17.2
12-month total rainfall to 31st December 2025: 580.4 Difference from average: -99.8
Sunshine (all totals in hours; all averages 1991-2020)
Total for the month: 47.7 Difference from average: -9.2
Percentage of the average: 84%
Mean daily sunshine: 1.5 Difference from average: -0.3
Sunniest day: 5.8 (2nd) 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 (m/s; all data from the West Building roof, Lower Mountjoy campus)
Average wind speed: 0.98
Maximum gust: 20.6 (8th, 11:15, W)
Pressure (mbar)
Average: 1011.6
Maximum: 1041.3 (27th, 10:15) Minimum: 984.2 (6th, 3:00)
Comments on December 2025
The mean air temperature of 6.30 °C was the 10th highest for December on record (since 1843). The mean maximum air temperature was the =17th highest and the mean minimum air temperature was the =9th highest. This reflected some very mild days in the first half of the month and a lack of very cold nights. The absolute minimum would have been very high for December had it not been for the sharp frost on the 31st; even so, -2.6 °C is the =32nd highest absolute minimum for any December in 176 years. There was the =2nd lowest number of air frosts (since 1900) and the 8th lowest number of ground frosts (since 1874). December’s rainfall total was close to average with fewer hours of bright sunshine than normal.
Note some potential problems with much of the data from the West Building AWS (4th – 18th), due to problems with the battery. This has now been sorted out, thanks to Dave Hodgson. The pressure data look OK throughout the month.
Emeritus Professor Tim Burt
Department of Geography
Durham University