Calais, ME 04668 Frost Dates
04668, near Calais, ME: the frost window
Typically, the last spring freeze lands around 05/04, roughly 249 days out. Fall's first freeze usually shows up around 10/10, roughly 157 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Calais in Zone 5b (-15 to -10°F average annual minimum); frost dates are NOAA's 1991-2020 station normal, not this year's forecast.
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.
The actual range around Calais's last frost
05/04 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 157 days separate Calais's last and first frost, putting it 33,323 of 40,283 ZIP codes nationally. Within ME, it ranks 195 of 456.
Learn more
Two guides worth reading on 04668: zone vs. frost date, on why Zone 5b and Calais's frost date answer different questions, and the frost range, on how to read the range around Calais's dates instead of trusting one.