15th July has a rhyme: St Swithin’s Day, if it does rain; Full forty days, it will remain; St Swithin’s Day, if it be fair; For forty days, t’will rain no more.
Celebrated (or berated as the case may be!) on July 15th, weather sayings pertaining to St. Swithin’s Day are probably the most famous or infamous in the UK. St. Swithin died in 862 and was buried outside Winchester Cathedral so that he could ‘feel’ the raindrops when he was dead. However, when he was canonised a tomb was built inside the cathedral and July 15th 971 was the day his body was to be moved. Legend has it that a storm broke on that day ending a long dry spell. Not only that – it continued to rain on each of the subsequent 40 days. As a result the monks took it as a sign of ‘divine displeasure’ and` left his body where it was.
Since 1861 there have never been 40 dry or 40 wet days following a dry or wet St. Swithin’s Day. In fact, on average, about 20 wet days and 20 rain free days can be expected between July 15th and August 24th. The summers of 1983, 1989, 1990 and 1995 were, however, near misses. During these summers July 15th was dry over southern England, as were 38 of the following 40 days. As for wet weather, BBC Meteorologist Philip Eden presented a report that on 15th July 1985 it rained in Luton and then rained on 30 of the subsequent 40 days.
The creators of the St. Swithin’s Day sayings during the Middle Ages would be aware that summer weather patterns are usually quite well established by mid-July and will then tend to persist until late August. It is not just England though; similar sayings exist for the same time of year in Belgium, the Netherlands, Germany and France.
If we modernise the sayings surrounding St. Swithin’s Day perhaps the sayings should be updated to read: St. Swithin’s Day, if it does rain, 40 days staying unsettled. St.Swithin’s Day, if it be fair, 40 days staying settled.”