Seven Sleepers' Day or Siebenschläfertag

Dormouse has always had a fixed date, June 27th. Until the 16th century, however, the day of the dormouse referred to the weather conditions at the end of the first week of July. The reason for this is the introduction of the Gregorian calendar in 1582. It corrected an inaccuracy in the previously valid Julian calendar and resulted in a shift of around 11 days. The original dormouse day is therefore July 7th or 8th.