This is a much used phrase at this time of year, particularly when we experience frosty nights and cool, sunny days. The message is that we need to be cautious about being lulled into thinking that warm weather is going to be the norm once we begin to feel the joys of springtime.
As far as is known this phrase was first mentioned in an Almanack of 1732 - “Leave not off a Clout till May be out”.
The word ‘clout’ is accepted to be an old term for a fragment of cloth or clothing. The real discussion begins about WHEN we should hang on to our thermals.
May is an alternative name for Hawthorn (Crataegus sp) which can produce its flowers in April and May, so could it mean that we should wait until the hawthorn blossom is out? After all, nature is good at judging when to act and the hawthorn will have ‘decided’ that milder conditions will now prevail and that frosts will not damage the delicate flowers and, by consequence, our bodies.
Or is it the actual month of May?
In 1855 the Whitby Gazette carried the following message. “Wind at North and East, was never good for man nor beast. So never think to cast a clout until the month of May is out”.
If, in earlier centuries, people didn’t have regular access to calendars it’s a nice thought that they could live by visual countryside clues. (The idea of “red skies at night - shepherds’ delight” as an indicator or good weather to come, in the days before the Met Office app, is a good example of this).
But what if people were unaware of the word May referring to hawthorn? Hawthorn has been a symbol of rebirth and fertility, as referenced by the appointment of ‘May Queens’. Pagan beliefs held that she was the sleeping goddess who awoke each spring, allowing nature to blossom and provide for the population after a hard winter. So it seems unlikely that many folk would not be tuned into the May plant.
The jury is still out on this but I like the appeal of the plant-based version. However, my advice would be to check your preferred weather app before setting out for a walk, whatever the time of year.