March 2009

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

Mean daily maximum: 11.0
Difference from average: +2.6

Mean daily minimum: 2.6
Difference from average: +1.0

Mean air temperature: 6.8
Difference from average: +1.8

Absolute maximum: 17.2 (18th)

Absolute minimum: -5.3 (5th)

Mean grass minimum: -23

Absolute grass minimum: -11.1 (5th)

Number of ground frosts: 23

Number of air frosts: 6

Mean soil temperature at 30cm depth: 6.9

Mean soil temperature at 100cm depth: 7.2

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

Total for the month: 21.2
Difference from average: -30

Percentage of the average: 41%

Wettest day: 10.6 (28th)

Number of rain days (>0.25mm): 8

Number of wet days (=> 1mm): 6

3-month total rainfall to 31st March: 96.1
Difference from average: -55.7

6-month rainfall total to 31st March: 251.6
Difference from average: -77.2

12-month rainfall total to 31st March: 774.8
Difference from average: +125.8

Humidity
(Averages for 09:00 hours GMT)

Relative Humidity: 76%

Sunshine
(all averages 1961 – 1990)

Total for the month: 176.2 hours
Difference from average: +70.7

Percentage of the average: 167%

Mean daily sunshine: 5.7 hours
Difference from average: +2.3

Sunniest day: 11.4 hours (29th)

Number of days with no recorded sunshine: 0

Cumulative total sunshine since 1st January: 241.3 hours
Difference from average: +16.6

Wind

The mean wind speed: 15.0km/h [8.1kt]
Difference from average: -0.8km/hr

The highest gust: 91.9km/h [49.6kt] from 233° at 04:14 GMT on 9th

ISSN1350-483

Comments on March 2009
This was the 15th warmest March since 1850, although 2000, 2002, 2003 were all warmer. The warmest March on record is 1938 (9.2°C). There was the 12th highest maximum for a March day since 1900 (18th), the warmest March day since 1991. However, there were the most ground frosts for March since 1980 and the lowest absolute grass minimum since 1950 (when my records begin for that variable), implying cold, clear nights. The mean minimum temperature was above average, but not greatly so.

It was the driest March since 2003, the 35th driest March on record since 1850. The driest March was in 1953 (1.3mm). There were the fewest number of rain days since 2004. The last three months have been the driest three months since Aug – Oct 2007, while the last six months have been the driest six-month period since April – September 2006. Looking at a slightly longer period, November to March inclusive, it has been the 36th driest period since 1850/51; 1999/2000 and 2003/4 were drier.

For the second month in a row, all days recorded sunshine. It was the 4th sunniest March since 1882, beaten only by 2003, 1907 and 1894.

Professor Tim Burt
Department of Geography
Durham University