New Haven, CT 06537 Frost Dates
06537, near New Haven, CT: the frost window
Typically, the last spring freeze lands around 04/17, roughly 232 days out. Fall's first freeze usually shows up around 10/27, roughly 193 days after the last spring frost.
New Haven sits in USDA Zone 7a (0 to 5°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
New Haven's growing season runs out in roughly 9 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
Why 04/17 isn't a guarantee
04/17 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/02 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/01 and only about 1 year in 10 sees frost after that.
New Haven against the rest of the dataset
At roughly 193 frost-free days, New Haven places 19,710 of 40,283 ZIP codes in this dataset. Within CT, it ranks 86 of 391.
Learn more
Two guides worth reading on 06537: local microclimates, on what one yard in New Haven can differ from the 06537 normal, and zone vs. frost date, on why Zone 7a and New Haven's frost date answer different questions.