First Frost Fast Approaching
The average date of the first fall frost (low temperature less than or equal to 32°F) ranges from late September in Caribou and Concord to mid- to late November in Washington, D.C. and the New York City area. For a majority of the 35 major climate sites, though, the average date is sometime in October.
Just because those are the average dates, doesn’t mean that’s when frost always occurs. For example, the earliest first fall frost occurred in summer! That’s right, Concord experienced a frost on August 29 in 1986 (and also in late August 1965 and 1976). On the other hand, the latest first fall frost happened a few days after the New Year - LaGuardia Airport had its first fall frost of 2015 on January 4, 2016.
Average, earliest, latest, and this year’s date of the first fall frost at the major climate sites.
This year, as of October 7, five major climate sites had experienced their first frost - Caribou, Concord, Burlington, Portland, and Binghamton. For four of these sites, the frost arrived within a few days of when it was expected; however, it was just over a week late in Concord, arriving on October 5 compared to the average date of September 27. For frost/freeze warnings in your area, visit the website of your local National Weather Service office. In early November look for our blog on the average date of the first measurable snow and first inch of snow!