did not rain on St. Medard Day. In accordance with the legend , it hasn't rained for 40 straight days, but it has in fact rained just about every day for the past three weeks. Now, let's talk about St. Swithin's Day... Ludi Ling Via Wikipedia Under Creative Commons St. Swithin's Day July 15 St. Swithin's Day in the United Kingdom also called St. Swithun's Day, is just like St. Medard Day in Acadiana. The legend says that if it rains on St. Swithin's Day, July 15, that it will rain for 40 days in a row. One positive twist with St. Swithin's Day is that if it rains on July 15, after the 40 days of rain will come 40 days of nice weather.