Predicting the date of the first frost is tricky. And while it may not cause gnashing of landscapers’ teeth like an unexpected late spring frost, the first fall frost is important to some.
Weather scientists have kept detailed records of frost occurrence for our area and they can offer some averages for guidance. While frost may not occur at an air temperature of 32 degrees, we’ll use that temperature as a reference point.
Weather people say that over their thirty year observation range, the average date of first frost is November 13. The earliest frost date was October 25 and the latest fall frost was December 6.
If we choose 16 degrees as the mark of severe cold weather, record keepers say there is a 90% chance of its occurrence before December 25 each year.
In spring, the average date it occurs is February 5 and the latest date that 16 degrees occurred in thirty years was March 4.
see also Predicting Last Frost