Extra - March 25, 2013
Coldest March for 44 years
Remarkable late-March snow

By Philip Eden


With a week still to go we are on course to register the coldest March, averaged over England and Wales, for at least 44 years and maybe for longer. Last year we had the warmest March since 1957, and it may be instructive to compare the character of the two months to understand how successive Marches can be so different.


March last year was dominated by high pressure systems, the afternoons were notably warm especially from the 21st onwards, there was a shortage of rain and a remarkable excess of sunshine. At Southampton the monthly sunshine total was 209 hours which is some 70 per cent above the local average.


March this year has given us relentless easterly winds; indeed the spell of easterlies began in mid-February. These winds have delivered air from northern Russia throughout that period except for a very short-lived spell around March 5 when the air came from the Mediterranean. There has been some snow on 12 of the 24 days of March so far, excessive rain too in eastern and southern districts, and a marked shortage of sunshine. So far this March sunshine aggregates have been below 40 hours in eastern Scotland and the north Midlands, some 50-60 per cent below the average for those areas.


Between the 23rd and 25th some very large amounts of snow have fallen, especially in the north Midlands, north Wales, southwest Scotland and Northern Ireland. Level snow depths have reached 30-50cm with drifts four metres high. Thousands of homes have been without electricity for several days.


March has become progressively warmer over the last 350 years: there were 16 colder Marches in the 18th century, 14 colder in the 19th century, but only five colder in the 20th century, and none since 1969.


Oddly, though, there have been many contrasting pairs, notably 1996 and '97, 1961 and '62, 1957 and '58, 1947 and '48, and 1937 and '38. Thus we shouldn't run away with the idea that a very cold March followed by a very warm one (or vice versa) is abnormal. Rather, it is probably more common than we realise.


Some meteorologists have, rather mischievously, suggested that, because last year's warm March was succeeded by a cool, wet summer, this year's cold March should be followed by a hot, dry one. Sadly, the statistics do not bear this out, suggesting instead that there is no relationship between March and the following summer. Of the ten warmest Marches, three were followed by warm summers, two by cool summers, and five by average summers. The summers following the ten coldest Marches came in at four warm, four cool, and three average.


By Philip Eden


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