Uncoupling the Legend of St Swithun

A subject, so often a topic of conversation with anyone living within our islands, is that of the weather. How many times do we grumble about it? We complain when it rained all the time, we complain when it's too hot, we complain when it's gets cold. 

When l was playing local cricket during the hot summer of 1976, sometimes it was so warm that it was a relief to be asked to do the scoring, as you could shade in the coolness of the pavillion, or hide away in the dark recesses of the scorebox.

Playing under burning skies on straw coloured outfields was not only uncomfortable, but also parched the throat. I remember playing in one particular match where in addition to the tea interval, there were three breaks for drinks; two in the afternoon and one at 7pm in the evening!

But it was certainly not the weather for cricket on July 15th in the year 971, (the invention of the game was still several centuries away) as it was absolutely pouring down with rain. It was raining so hard that those who were charged with the task of exhuming the buried remains of the former Bishop of Winchester, Swithun, recently made patron of the restored church by the Anglo-Saxon church reformers, were unable to start work. Eventually, the rain did cease and St Swithun was able to take his rest inside the cathedral.

Like many legends, the mystique surrounding the actual happening was left to chronicles of later generations, and around 1315, the Durham chronicles, it is believed, were credited with the fable that if it rains on St Swithun's Day (15th July), it will rain for the next forty days. 

Well, you may just dismiss this as meteorological claptrap. But the legend may convey a hint of truth. 

Our weather in the British Isles is heavily influenced by strong winds in the lower atmosphere moving from west to east called the Jet Stream. 

In summertime, the Jet often moves more slowly like a meandering river in a series of loops, bows, twists and turns. If it settles to the north of our islands, this will allow high pressure continental air masses to build up over the country, giving long spells of warm and settled weather. 

But if the Jet is pushed further south towards the Bay of Biscay, or lies across the British Isles, unsettled and cooler conditions from the north prevail with frequent rain expected. 

The Jet has the tendency to settle itself around mid-July, the time of the feast day of St Swithun, and sometimes doesn't move until the August Bank Holiday weekend, or early September. About forty days later. 

So the chronicles, without the aid of computers or weather satellites, may have unwittingly reported a pattern in our weather and attached it to the legend of a saint. 

~Phil Wells