Today is the date of the average first frost of fall. Average is the key word here, as the first frost usually happens anytime from mid-September to mid-October.
The average date floats around a bit. The National Weather Service calculates averages based on the three most recent complete decades. This allows averages to change as the climate changes.
The current averages are based on the years 1981-2010. Twenty-five years ago, when averages were based on 1951-1980, the average first frost date was five days earlier on Sept. 25.
There has been no change in the average last frost in spring. That date is still May 12.
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