Frost Dates in Maine

At the middle station of the 50 in Maine where a freeze comes every year, the last spring frost (50%) is May 7 and the first fall frost October 5, a freeze-free season of 150 days. The last frost is earliest at Calais (Woodland, ME, April 21) and latest at Houlton (Houlton International Airport, ME, May 27), 36 days apart. The season runs from 115 days at Houlton to 185 at Calais.

37 of these stations were also in NOAA's previous normals, for 1981–2010. Between the two, the median station's freeze-free season grew 4 days longer, with the last spring frost 2 days earlier and the first fall frost 2 days later; the season lengthened at 31 stations and shortened at 4. The two periods share twenty years, so the change reflects mostly 2011–2020 against 1981–1990.