Calais, ME 04413 Frost Dates
04413, near Calais, ME: the frost window
The last spring frost here typically falls around 05/06, about 251 days from today. Fall's first freeze usually shows up around 10/08, roughly 155 days after the last spring frost.
Zone 5a (-20 to -15°F average annual minimum) comes from the USDA Plant Hardiness Zone Map; the frost dates above are the 1991-2020 normal at the nearest reporting NOAA station for Calais, not a forecast for this year.
Stretching the season past the first frost
Calais's growing season runs out in roughly 6 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
How much risk comes with planting early here
05/06 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/26 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/18 and only about 1 year in 10 sees frost after that.
Calais against the rest of the dataset
Calais's growing season runs about 155 days, ranking 33,981 of 40,283 US ZIP codes measured here, longest to shortest. Within ME, it ranks 202 of 456.
Learn more
Two guides worth reading on 04413: local microclimates, on what one yard in Calais can differ from the 04413 normal, and zone vs. frost date, on why Zone 5a and Calais's frost date answer different questions.