Spring Is Here!

For meteorologists, winter is over and spring sprang this morning. Some, of course, might think us somewhat hasty in bringing winter to a close so soon; astronomers, for instance, celebrate the birth of spring at the vernal equinox in two or three weeks time. Others inhabit an ancien regime, a time-warp in which the season starts a month ago. But for us, March and spring are perennial twins, forever born again today.

March is an adolescent month, always unsure of itself and full of bluff and bluster. At times it has an atavistic streak, reverting to its wintry origins, but now and then its lengthening days show promise, and hint at better times to come. Because of its boisterous winds, the ancient Saxons called it ‘rough month’, Hreth-monath; to the revolutionary French it was Ventose - ‘the windy one’; we, on the other hand, call it irrelevantly as Mars, the Roman god of war.

If March this year were to behave according to the norm, it would see Ireland for much of the time under the infuence of a regular procession of vigorous depressions, each one following the other across the Atlantic at intervals of 36 hours or so. Their energy derives from the contrast in temperature between the equator and the poles, which is near maximum at this time of year. It was a typical March depression, for example, which sank the HMS Eurydice of Ventnor in March 1878, and caused Gerard Manley Hopkins to exclaim:

And you were a liar, O blue March day.

A beetling baldbright cloud through England
Riding: there did storms not mingle? and
Hailropes hustle and grind their
Heavengravel? wolfsnow, worlds of it, wind there?

Those of you who have mastered Finnegans Wake in its entirety will immediately grasp precisely what he means.

Yet despite its reputation as a windy month, the average wind speed in Ireland in March is signifcantly less than that in February, and there are fewer gales. The reason is probably related to the average paths of the Atlantic depressions, which with the onset of spring tend to follow a more northerly track, and so most of them have a less devastating effect on our island than their winter cousins.

The air temperature in March often rises to an average of 10 or 11oC each day. The highest March temperature ever recorded in Ireland was 24 degrees in Dublin in 1965, and the lowest was minus 17 degrees on 3 March in the memorably cold year of 1947. Usually there is a marked decrease this month, compared to February, in the occurrence of both ground and air frost.

Rainfall in March, normally between 50 and 100mm in low-lying areas, marks the transition between January and February - statistically the two wettest months of the Irish year - and the relatively dry period we normally enjoy from April through to June.

Brendan McWilliams’ column, Weather Eye, was published daily in The Irish Times for almost two decades, and now is available as Illustrated Weather Eye from Gill Books.