January 2019

Temperatures
(all temperatures in degrees Celsius; all averages 1961 – 1990)

Mean daily maximum: 6.8
Difference from average: +0.2

Mean daily minimum: 1.3
Difference from average: +0.4

Mean air temperature: 4.0
Difference from average: +0.2

Absolute maximum: 11.9 (13th)

Absolute minimum: -6.6 (31st)

Mean grass minimum: -1.0

Absolute grass minimum: -9.4 (31st)

Mean concrete minimum: -0.2

Absolute concrete minimum: -5.9 (31st)

Number of ground frosts: 18

Number of air frosts: 12

Mean soil temperature at 30cm depth: 5.0

Mean soil temperature at 100cm depth: 6.8

Rainfall
(all totals in millimetres; all averages 1961 – 1990)

Total for the month: 11.8
Difference from average: -40.5

Percentage of the average: 22.6

Wettest day: 3.2 (26th)

Number of rain days (>0.25mm): 15

Number of wet days (=> 1mm): 3

3-month total rainfall to 31st January: 118.0
Difference from average: -54.0

6-month rainfall total to 31st January: 265.2
Difference from average: -81.0

12-month rainfall total to 31st January: 575.8
Difference from average: -73.2

Humidity
(averages for 09:00 hours GMT)

Relative Humidity: 79%

Sunshine
(all averages 1961 – 1990)

Total for the month: 74.5 hours
Difference from average: +14.0

Percentage of the average: 123%

Mean daily sunshine: 2.4 hours
Difference from average: +0.5

Sunniest day: 7.1 hours (23rd)

Number of days with no recorded sunshine: 0

ISSN1350-483

Comments on January 2019
Although mean air temperature was only modestly above average, this was nevertheless the equal 56th warmest January in 170 years, not quite in the upper quartile. Maximum temperatures were more above average than minimum temperatures, reflecting the dry, sunny conditions. This was the 7th driest January since 1850, the driest since 1989. It was the 13th sunniest January since 1881.

Note that I have now moved to using 19812010 averages. I am also using wind data from the automatic weather station on the roof of the West Building at the University’s Lower Mountjoy campus. The anemometer at the Observatory has been defunct for a decade now so at least the West Building data give some indication of recent conditions but there is no long-term average to compare with, of course.

Emeritus Professor Tim Burt
Department of Geography
Durham University