May 11 - Three Chilly Saints. May 11, 12, and 13 are the feast days
of Saints Mamertus, Pancras, and Gervais (or Gervatius). These three
are known as the Three Chilly Saints not because they were cold
during their lifetimes, but because these days are traditionally the
coldest of the month. English and French folklore (and later
American) held that these days would bring a late frost.