Calais, ME 04671 Frost Dates
Calais, ME: when does the frost end?
Around 05/05 is the usual last spring frost, about 250 days away. Fall's first freeze usually shows up around 10/13, roughly 160 days after the last spring frost.
Calais sits in USDA Zone 5b (-15 to -10°F average annual minimum). The dates above are NOAA's 1991-2020 normal at the nearest reporting station, a 30-year average, not a forecast.
Stretching the season past the first frost
With roughly 7 weeks until Calais's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
Why 05/05 isn't a guarantee
05/05 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/24 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
About 160 days separate Calais's last and first frost, putting it 32,325 of 40,283 ZIP codes nationally. Within ME, it ranks 154 of 456.
Learn more
Before leaning on 04671's figures: the frost range explains how to read the range around Calais's dates instead of trusting one, while local microclimates explains what one yard in Calais can differ from the 04671 normal.