Cold spell in May .....Just blame the 'Ice Saints'

May 11th is the day of St. Mamertus, May 12th of St. Pancratius, May 13th of St. Servatius, and May 14th of St. Boniface.	1
“Ces saincts passent pour saincts gresleurs, geleurs, et gateurs du bourgeon.”—Rabelais.

Basically this weather folklore is very well known in Belgium, France, Switzerland, Germany, and Austria. Here is an English translation of the information I found in German about the “Eisheiligen”. (May 99)

Are the “Ice Saints” out of tune??

Many of the old weather rules are forgotten. Nowadays, we rather rely on the weather forecast of radio and television. The “Ice Saints” are known for a cooling trend in the weather between 11th and 15th of May. 

For centuries this well-known rule had many gardeners align their plantings after it. Observations of weather patterns over many years have shown, however, that a drop in temperature occurs frequently only around May 20. 

Are the “Ice Saints” not in tune anymore? The mystery solution is found in the history of our calendar system: Pope Gregory VIII arranged a calendar reform in 1582, whereby the differences of the Julian calendar could be corrected to the sun year to a large extent. 

The day of the “Cold Sophie” (May 15) was the date in the old calendar and corresponds to today’s May 22. Therefore the effects of the “Ice Saints” is felt in the timespan of May 19-22. Sensitive transplants should only be put in the garden beds after this date.