Dover, NH 03902 Frost Dates
When can you plant in Dover, NH?
Around 05/09 is the usual last spring frost, about 254 days away. The first fall frost typically arrives around 10/03, about 146 frost-free days later.
The USDA Plant Hardiness Zone Map puts Dover in Zone 6a (-10 to -5°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
About 5 weeks of growing season left in Dover before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
The actual range around Dover's last frost
05/09 is the middle of 30 years of NOAA records, not a promise. Plant by 04/28 and you're betting against frost in roughly 9 years out of 10. 05/22 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Dover compares
Dover's growing season runs about 146 days, ranking 36,016 of 40,283 US ZIP codes measured here, longest to shortest. Within NH, it ranks 163 of 260.
Learn more
local microclimates covers what one yard in Dover can differ from the 03902 normal. zone vs. frost date covers why Zone 6a and Dover's frost date answer different questions.