(July 15), one of the several days from which, in folklore, the weather for a subsequent period is dictated. In popular belief, if it rains on St. Swithin's Day, it will rain for 40 days, but, if it is fair, 40 days of fair weather will follow. St. Swithin (b. c. 800 near Winchester, Hampshire—d. July 2, 862) was bishop of Winchester from 852 to 862. At his request he was buried in the churchyard, where rain and the steps of passersby might fall on his grave. According to legend, after his body was moved inside the cathedral on July 15, 971, a great storm ensued.

Weather frequently changes around midsummer, and thus the tradition that this day influences the weather may stem from ancient pagan belief. On the European continent similar beliefs are attached to other saints (e.g., St. Médard, June 8, France).