Somersworth, NH 03901 Frost Dates
Frost dates for Somersworth, NH, ZIP 03901
Around 04/30 is the usual last spring frost, about 245 days away. The first fall frost typically arrives around 10/09, about 161 frost-free days later.
Somersworth sits in USDA Zone 6a (-10 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.
What to do before the first frost
Zone 6a around Somersworth 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.
How much risk comes with planting early here
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 Somersworth compares
Somersworth's growing season runs about 161 days, ranking 31,998 of 40,283 US ZIP codes measured here, longest to shortest. Within NH, it ranks 67 of 260.
Learn more
the frost range explains how to read the range around Somersworth's dates instead of trusting one, and local microclimates explains what one yard in Somersworth can differ from the 03901 normal.