January 2010

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

Mean daily maximum: 3.4
Difference from average: -2.4

Mean daily minimum: -0.9
Difference from average: -1.1

Mean air temperature: 1.3
Difference from average: -1.7

Absolute maximum: 9.2 (18th)

Absolute minimum: -8.9 (8th)

Mean grass minimum: -1.5

Absolute grass minimum: -7.2 (19th)

Number of ground frosts: 16

Number of air frosts: 16

Mean soil temperature at 30cm depth: 2.9

Mean soil temperature at 100cm depth: 5.4

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

Total for the month: 59.8
Difference from average: +0.8

Percentage of the average: 101%

Wettest day: 11.6 (10th)

Number of rain days (>0.25mm): 20

Number of wet days (=> 1mm): 14

3-month total rainfall to 31st January: 297.2
Difference from average: +118.7

6-month rainfall total to 31st January: 389.8
Difference from average: +36.1

12-month rainfall total to 31st January: 769.5
Difference from average: +120.5

Humidity
(Averages for 09:00 hours GMT)

Relative Humidity: 86%

Sunshine
(all averages 1961 – 1990)

Total for the month: 63.8 hours
Difference from average: +10.0

Percentage of the average: 119%

Mean daily sunshine: 2.1 hours
Difference from average: +0.4

Sunniest day: 7.6 hours (31st)

Number of days with no recorded sunshine: 3

Wind

The mean wind speed: 13.0km/h [7kt]
Difference from average: -2.0km/hr

The highest gust: 69.3km/h [37.4kt] from 232° at 11:57 GMT on 27th

ISSN1350-483

Comments on January 2010
This was the coldest January in Durham since 1987. The mean maximum temperature this year was the same as the mean air temperature last year! It was the 143rd coldest in 161 years; in other words, only 18 Januaries have been colder since 1850.

It is likely that snow cover has affected the grass minimum temperatures observed.

The anemometer remains faulty but there were data from enough days to allow a tentative average to be calculated.

Professor Tim Burt
Department of Geography
Durham University