September 2003

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

Mean daily maximum: 18.3
Difference from average: +1.6

Mean daily minimum: 8.8
Difference from average: +0.1

Mean air temperature: 13.6
Difference from average: +0.9

Absolute maximum: 24 (18th)

Absolute minimum: 3.2 (24th)

Mean grass minimum: 6.5

Absolute grass minimum: 0.2 (24th)

Number of ground frosts: 0

Number of air frosts: 0

Mean soil temperature at 30cm depth: 14.9

Mean soil temperature at 100cm depth: 15.5

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

Total for the month: 24
Difference from average: -31.6

Percentage of the average: 43%

Wettest day: 10.4 (21st)

Number of rain days (>0.25 mm): 6

Number of wet days (=> 1 mm): 4

3-month total rainfall to 30 September 2003: 90.4
Difference from average: -84.1

6-month rainfall total to 30 September 2003: 179.2
Difference from average: -147.1

12-month rainfall total to 30 September 2003: 520.6
Difference from average: -128.4

Humidity
(Averages for 09:00 hours GMT)

Relative Humidity: 76.3%

Sunshine
(all averages 1961 – 1990)

Total for the month: 130.4 hours
Difference from average: +6.4

Percentage of the average: 105%

Mean daily sunshine: 4.3 hours
Difference from average: +0.2

Sunniest day: 8.8 hours (14th)

Number of days with no recorded sunshine: 2

Cumulative total sunshine since 1st January: 1252.1 hours
Difference from average: +127.6

Wind

The mean wind speed: 9.3km/h [5kt]
Difference from average: +1.4 km/hr

The highest gust: 53.7km/h [29kt] from 231° at 01:58 GMT on 18th.

ISSN1350-483

Comments on September 2003
September was another warm month, above average mainly because of higher than normal daytime temperatures. Overall, it was the warmest September since 1999 but, that year apart, the warmest September since 1981. It ranks 20th equal warmest since 1852.

Rainfall was well below average, despite a total of 10.4mm on the 21st. There were only 6 “rain days” and 4 “wet days”. Long-term totals remain well below average, most especially the 6-month total, which ranks 44th lowest of all possible 6-month totals since 1850.

Sunshine was only a little above average despite it being quite dry, with the number of days with no sunshine the lowest since 1998.

Professor Tim Burt
Department of Geography
Durham University