St Swithin's day 
noun
15 July, a Church festival commemorating St Swithin and popularly believed to be a day on which, if it rains, it will continue raining for the next forty days.Saturday was St Swithin's day and even the weather men were speaking gloomily of the likelihood of it raining, and going on to rain for forty days, just like the legend has it....
- St. Swithin's Day has rather justified the reputation of its weather forecast this year, and now everybody is looking forward anxiously to the fortieth day in the hope that new conditions of weather will result.