December 2023
SUMMARY OF THE METEOROLOGICAL READINGS AT DURHAM UNIVERSITY OBSERVATORY
December 2023
Temperatures (all temperatures in degrees Celsius; all averages 1991-2020)
Mean daily maximum: 8.6 Difference from average: +1.5
Mean daily minimum: 3.2 Difference from average: +1.8
Mean air temperature: 5.9 Difference from average: +1.7
Absolute maximum: 14.0 (24th)
Absolute minimum: -6.9 (2nd)
Mean grass minimum: 2.0 Difference from average: +2.3
Absolute grass minimum: -4.9 (6th)
Mean concrete minimum: 2.2
Absolute concrete minimum: -3.6 (6th)
Number of ground frosts: 10 Difference from average: -6
Number of air frosts: 7 Difference from average: -4
Mean soil temperature at 300 mm depth: 6.7
Mean soil temperature at 1000 mm depth: 8.6
Rainfall (all totals in millimetres; all averages 1991-2020)
Total for the month: 117.6 Difference from average: +56.4
Percentage of the average: 192%
Wettest day: 38.0 (4th)
Number of rain days (>0.1 mm): 20 Difference from average: +1
Number of wet days (=>1.0 mm): 15
3-month total rainfall to 31st December 2023: 350.4 Difference from average: +150.7
6-month total rainfall to 31st December 2023: 600.0 Difference from average: +215.4
12-month total rainfall to 31st December 2023: 837.2 Difference from average: +156.2
Sunshine (all totals in hours; all averages 1991-2020)
Total for the month: 43.7 Difference from average: -13.2
Percentage of the average: 77%
Mean daily sunshine: 1.5 Difference from average: -0.4
Sunniest day: 5.8 (11th)
Number of days with no recorded sunshine: 1
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: 7.9
Maximum gust: 98.2 (21st, 05:45, WNW)
Comments on December 2023
Notwithstanding some cold days at the start of the month, including an ‘ice day’ on the 2nd (maximum temperature -0.7 °C), this was the 15th warmest December on record since 1843. The mean maximum is the equal 15th highest and the mean minimum the equal 13th highest. Christmas Eve was the equal 32nd warmest December day since 1843 (n=5611). This was the 11th wettest December since 1850. Remarkably, the total of 38 mm recorded on the 4th is the wettest December day on record, beating the previous record: 37.4 on 16th December 1872 (1872 is the second wettest year at Durham, behind 2012). The estimated amount of sunshine was 43.7 hours although in fact the AWS recorded 61.7 hours, showing that exposure during the winter months is OK. There was a gust of 98.2 kph on the 21st.
Following last year’s record-breaking mean air temperature (10.59 °C), 2023 was the 2nd warmest year on record (10.35 °C). Not surprisingly, the decadal running mean has now reached 9.9 °C, easily the highest on record. Of the individual months, only April fell below mean air temperature. This was the sixth wettest year on record (837.2 mm, 157mm above average, 123%), the wettest year since the record-holder 2012 (1018 mm). Summer and particularly autumn were well above average, winter and spring below average. Sunshine hours were just a little above average (103%, 1508 hours).
Emeritus Professor Tim Burt
Department of Geography
Durham University