St Swithun's day - fact or meteorological myth? According to folklore today's weather will set the trend for the next forty days:
St Swithun's Day, if it does rain
Full forty days, it will remain
St Swithun's Day, if it be fair
For forty days, t'will rain no more
St Swithun was a monk who died around 862 AD and, according to legend, he requested his burial in the churchyard of the Old Minster (cathedral) at Winchester, in a spot where "the sweet rain from heaven might wet his grave."
The legend says that when his remains were moved inside the cathedral on the 15th of July, his spirit was supposedly so outraged that it rained for the next forty days. A romantic story - but lacking accuracy according to the Met Office:
– Met Office
Unfortunately the weather rhyme which stemmed from this legend just doesn't stack up. Since the start of records in 1861, there has never been a record of 40 dry or 40 wet days in a row following St Swithun's Day. So you can't make a 40-day forecast out of a rhyme and today's weather.