New Haven, CT 06721 Frost Dates
Frost dates for New Haven, CT, ZIP 06721
Typically, the last spring freeze lands around 04/17, roughly 232 days out. The first fall frost typically arrives around 10/27, about 193 frost-free days later.
The USDA Plant Hardiness Zone Map puts New Haven in Zone 6b (-5 to 0°F average annual minimum); frost dates are NOAA's 1991-2020 station normal, not this year's forecast.
What to do before the first frost
Zone 6b around New Haven has about 9 weeks left before the first fall frost — that's the usual window to get a cold frame up if you want to keep harvesting past it.
Why 04/17 isn't a guarantee
04/17 is the middle of 30 years of NOAA records, not a promise. Plant by 04/02 and you're betting against frost in roughly 9 years out of 10. 05/01 is the safer bet, historically only a 1-in-10 chance of frost that late.
How New Haven compares
At roughly 193 frost-free days, New Haven places 19,716 of 40,283 ZIP codes in this dataset. Within CT, it ranks 92 of 391.
Learn more
zone vs. frost date explains why Zone 6b and New Haven's frost date answer different questions, and the frost range explains how to read the range around New Haven's dates instead of trusting one.