By Philip Eden

Much of the southern coast of England enjoys almost 1800 hours of sunshine in a typical year, roughly three-quarters more than the western highlands of Scotland where the long-term average is only marginally above 1000 hours. The difference is largely due to the prevailing south-westerly and westerly winds which deliver copious amounts of moisture, in the form of clouds and rain, to north-western Britain whereas the air affecting the south-eastern quarter of the country is appreciably drier and thus less cloudy.

This contrast between North-west and South-east is least apparent during spring when south-westerly winds are at their least frequent. In April and May the normal pattern is reversed: the average sunshine for May in London is 200 hours and in the Midlands just 180 hours, compared with 205 hours on the Isle of Skye and 235 hours on Tiree in the Inner Hebrides. This reflects a peak at this time of the year in the frequency of north-easterly winds which deliver extensive cloud and fog (the local name for this is "haar") from the North Sea to eastern England and eastern Scotland, while western Scotland and northwest England benefit from the shelter provided by the Western Highlands and the Lake District.

The weather during the last week of April provided a perfect illustration of these north-easterlies at work. During the last ten days of the month the sun shone for a total of 88 hours at Tiree, 76 hours at Stornoway on the Isle of Lewis, and 74 hours at Dundrennan in Kirkcudbrightshire, while in eastern England there was only 35 hours of sunshine at Boulmer on the Northumberland coast, 25 hours at Leeming in North Yorkshire and 25 hours also at Leconfield in the East Riding of Yorkshire during the same period.

As one might expect, these north-easterly winds have also had an impact on temperatures, which soared into the seventies in Strathspey where Aviemore reached 22.0°C on April 28, but struggled to reach the fifties along the east coast of England. On April 25, for instance, at Inverbervie on the Kincardineshire coast the day's maximum was a mere 7.2°C.

Last week brought us south-westerly winds, and that means that the warmest and brightest weather was found in eastern England - a welcome relief, no doubt, from the recent cold and gloom.

© Philip Eden