Caribou, ME 04781 Frost Dates
04781, near Caribou, ME: the frost window
Typically, the last spring freeze lands around 05/23, roughly 268 days out. Fall's first freeze usually shows up around 09/24, roughly 121 days after the last spring frost.
Caribou sits in USDA Zone 4a (-30 to -25°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
Caribou's growing season runs out in roughly 4 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
05/23 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 05/08 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 06/06 and only about 1 year in 10 sees frost after that.
Caribou against the rest of the dataset
About 121 days separate Caribou's last and first frost, putting it 39,001 of 40,283 ZIP codes nationally. Within ME, it ranks 439 of 456.
Learn more
Two guides worth reading on 04781: zone vs. frost date, on why Zone 4a and Caribou's frost date answer different questions, and the frost range, on how to read the range around Caribou's dates instead of trusting one.