Caribou, ME 04750 Frost Dates
Caribou, ME: when does the frost end?
Typically, the last spring freeze lands around 05/16, roughly 261 days out. Fall's first freeze usually shows up around 09/24, roughly 129 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
With roughly 4 weeks until Caribou's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
Why 05/16 isn't a guarantee
05/16 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 05/01 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 06/01 and only about 1 year in 10 sees frost after that.
Caribou against the rest of the dataset
Caribou's growing season runs about 129 days, ranking 38,451 of 40,283 US ZIP codes measured here, longest to shortest. Within ME, it ranks 428 of 456.
Learn more
Before leaning on 04750's figures: zone vs. frost date explains why Zone 4a and Caribou's frost date answer different questions, while the frost range explains how to read the range around Caribou's dates instead of trusting one.