Saint Swithun’s day (July 15th) forecasts the weather for the summer.
The Saint Swithun’s day weather proverb:
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 (no more).
This saying dates back to Anglo-Saxon times and the burial of St Swithun, the Bishop of Winchester Catherdral. One local legend suggests the proverb originates from the day the saint’s remains where moved from the graveyard to a tomb. To show his displeasure with his new, more sheltered home, the saint summoned a storm onto the town which held for 40 days.
Saints are not science but there may be some validity to the saying if meteorologists look to the weather in mid-July as a way to predict the weather pattern over the next 40 days. That is because around this time the jet stream, one of the biggest influencing forces on our weather system, predictably takes one of two paths.
If the jet stream seeeps south, it will pull in cold air from the Arctic bringing with it clouds and rain. If the stream moves further north, it will pull warm sub-tropical air from the south and lead to a sunny, warmer late summer.
Say a prayer to Saint Swithun today to move that jet stream north so August isn’t a rain out. then check the weather map.