Seven Sleepers Day

Source: http://www.google.com/logos/sevensleepers09.gif

In Germany, June 27 is Siebenschläfertag (Seven Sleepers Day). The weather on that day is supposed to determine the average weather of the next seven weeks. This is one of the most well-know bits of traditional farmers' weather lore remaining in today's Germany (this and the Ice Saints are the only ones still know to a majority of the adult population), but quite inaccurate in practice. [Read more on Wikipedia]