Rochester, NH 03855 Frost Dates
Frost dates for Rochester, NH, ZIP 03855
Typically, the last spring freeze lands around 04/30, roughly 245 days out. The first fall frost typically arrives around 10/09, about 161 frost-free days later.
The USDA Plant Hardiness Zone Map puts Rochester in Zone 5b (-15 to -10°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 5b around Rochester has about 6 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 04/30 isn't a guarantee
04/30 is the middle of 30 years of NOAA records, not a promise. Plant by 04/18 and you're betting against frost in roughly 9 years out of 10. 05/13 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Rochester compares
Rochester's growing season runs about 161 days, ranking 31,959 of 40,283 US ZIP codes measured here, longest to shortest. Within NH, it ranks 61 of 260.
Learn more
local microclimates explains what one yard in Rochester can differ from the 03855 normal, and zone vs. frost date explains why Zone 5b and Rochester's frost date answer different questions.