Maine frost dates

Across Maine, the average last spring frost is around May 14 and the average first fall frost around September 25 — roughly 134 frost-free days. USDA zones 3b, 4a, 4b, 5a, 5b, 6a.

Risk you accept	Last spring frost by	First fall frost by
Cautious (~10%)	May 28	September 11
Average (~50%)	May 14	September 25
Gambler (~90%)	April 30	October 9

→ Turn these into sowing dates with the Maine planting calendar, or look up an exact ZIP code.

Statewide average from NOAA/NCEI freeze normals. Cautious/gambler dates are about two weeks either side of the average.