St Swithun's Day - A Modern Take?

Tuesday 15th Jul 2014 by theWeather Club

St Swithun’s day if thou dost rain

For forty days it will remain

St Swithun’s day if thou be fair

For forty days ‘twill rain nae mare

St Swithun's Day is today and the forecasts predict that it will be mainly dry in the UK. However, according to weather lore, if it does rain today it could rain for another 40 days!

The legend of St Swithun (or St Swithin) dates back to the ninth century and although its origins are widely disputed, some parts can be sifted out as probably true. St Swithun was an Anglo-Saxon bishop of Winchester who died around AD862. St Swithun asked to be buried among the normal people outside in the churchyard. However when he was later made a saint his body was dug up and moved indoors.

This unwanted move apparently upset the heavens so much that a terrible downpour struck and continued for 40 days, giving rise to the legend that rain on that day would lead to 40 days' of rain. It must be said, however, that there is no hard evidence that the heavens opened during the reburial and no early account that mentions rain during the second interment.

Of course the legend also states that if no rain falls on St Swithun's day, there will be no rain for 40 days, but again this does not stand up to the facts. No 40 day drought has been recorded anywhere in the UK, nor 40 consecutive days of rainfall.

Even with all of those caveats, there could be a glimmer of logic in the old legend as the middle of July tends to be when the jet stream settles into a relatively consistent pattern. If it lies to the north of the UK throughout summer then continental high pressure can move in bringing warmth and sunshine, but if it stays further south then Arctic air and Atlantic weather systems may predominate, bringing colder, wetter weather.

So for today's world with our records and forecasts, maybe the rhyme could be reworded to:

St Swithun's day if thou dost rain

For forty days, relatively unsettled there's a fair chance it will remain

St Swithun's day if thou be fair

For forty days, a northerly jet stream might result in some fairly decent spells But then again it might not