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New Hampshire Frost Dates: Last and First Frost by Town

55 NOAA weather stations · 1991–2020 U.S. Climate Normals · Data updated 2026-10-29

Quick answer

Across New Hampshire's 54 NOAA stations with regular frost, the median last spring frost is May 8 and the median first fall frost is October 4. Last frost dates range from April 21 at Manchester Airport to May 31 at Colebrook 3SW, so enter your ZIP code below for the station nearest you.

How frost dates vary across New Hampshire

  • Elevation matters: across New Hampshire's stations, each 1,000 ft of elevation delays the median last frost by about 13 days.
  • North vs south: stations in the northern third of the state (north of 43.9°N) reach their median last frost about 15 days later than the southern third (south of 43.1°N).
  • Safety margin: the median 10%-risk date (May 22) is about 14 days after the median last frost. Waiting until then cuts the chance of a killing frost on tender transplants from 1 in 2 to 1 in 10.

Frost dates at New Hampshire's major weather stations

These National Weather Service stations, mostly at airports, have the longest and most complete records in the state.
Berlin Municipal Airport1,158May 30Jun 11Sep 19112
Concord Municipal Airport346May 8May 22Oct 3146
Durham 2 N119May 3May 16Oct 10158
Durham 2 SSW63May 7May 19Oct 4150
Jaffrey Municipal Airport1,040May 5May 20Oct 6152
Lebanon Municipal Airport598May 9May 24Oct 6148
Manchester Airport225Apr 21May 6Oct 19180
Mount Washington6,267Any monthAny monthAny month66
Rochester Skyhaven Airport323Apr 30May 13Oct 9161
Whitefield Mount Washington Airport1,074May 27Jun 10Sep 19116

All 55 stations in New Hampshire

Last frost and first frost are medians: a 50% chance of a 32°F night after (spring) or before (fall) that date. 10% risk is the spring date with only a 1-in-10 chance of a later frost. Click a column to sort.
Benton 5 SW1,200May 15Jun 3Sep 28133
Berlin920May 14May 30Sep 30135
Berlin Municipal Airport1,158May 30Jun 11Sep 19112
Bethlehem 21,180May 24Jun 8Sep 18116
Bradford 2815May 15May 29Sep 27135
Colebrook 3SW1,120May 31Jun 14Sep 21112
Concord Municipal Airport346May 8May 22Oct 3146
Durham75May 8May 22Oct 4148
Durham 2 N119May 3May 16Oct 10158
Durham 2 SSW63May 7May 19Oct 4150
E Milford240Apr 28May 12Oct 8161
E Sandwich692May 6May 19Oct 6151
Epping160May 7May 21Oct 4148
Errol Airport1,240May 21Jun 3Sep 22123
First Connecticut Lake1,650May 25Jun 8Sep 24121
Franklin Falls Dam450May 7May 20Oct 3148
Gorham Airport800May 14May 29Sep 26133
Grafton830May 21Jun 5Sep 26127
Greenland95May 4May 18Oct 8157
Greenville 1 NNE900May 10May 27Oct 6147
Hanover584May 1May 15Oct 13162
Hopkinton Lake430May 6May 20Oct 1146
Hudson 1 SSE185May 3May 16Oct 8156
Jaffrey Municipal Airport1,040May 5May 20Oct 6152
Jaffrey Silver Rch Airpark1,030May 5May 19Oct 6154
Jefferson1,235May 8May 23Oct 1146
Keene511May 14May 28Oct 1138
Lakeport 2500Apr 30May 13Oct 18170
Lancaster860May 18Jun 1Sep 30132
Lebanon Municipal Airport598May 9May 24Oct 6148
Lincoln Nepp807May 7May 19Oct 4149
Manchester Airport225Apr 21May 6Oct 19180
Massabesic Lake253Apr 30May 14Oct 11164
Meredith 3 NNE861Apr 28May 9Oct 16171
Milford320May 3May 15Oct 5156
Mount Sunapee1,275May 2May 17Oct 9158
Mount Washington6,267Any monthAny monthAny month66
N Conway522May 7May 19Oct 5150
N Stratford950May 19Jun 2Sep 29131
Nashua 2 NNW135Apr 30May 11Oct 12165
Nashua Cwsu180Apr 29May 11Oct 8162
Newport770May 14May 29Oct 1140
Pinkham Notch2,025May 18Jun 1Oct 1135
Plymouth660May 20Jun 4Sep 27128
Rochester Skyhaven Airport323Apr 30May 13Oct 9161
Salisbury550May 14May 28Sep 29138
Tamworth 4541May 16May 30Sep 26129
W Hampstead288Apr 30May 14Oct 11162
Walpole 2S Nepp604May 8May 22Oct 3149
Waterville Valley Nepp1,429May 15May 29Sep 28134
Weare720May 2May 14Oct 8158
Weare 2 NE805May 9May 23Oct 5148
Wentworth653May 12May 25Oct 6146
Whitefield Mount Washington Airport1,074May 27Jun 10Sep 19116
York Pond1,519May 23Jun 6Sep 22122

Frequently asked questions

When is the last frost in New Hampshire?

The median last spring frost (32°F) across New Hampshire's NOAA weather stations is May 8, based on 1991–2020 climate normals. It ranges from April 21 at Manchester Airport to May 31 at Colebrook 3SW. For a safer planting date, use the 10%-risk date; the state median for that is May 22.

When is the first frost in New Hampshire?

The median first fall frost across New Hampshire's stations is October 4. The earliest median first frost is September 18 at Bethlehem 2, and the latest is October 19 at Manchester Airport.

How long is the growing season in New Hampshire?

The median frost-free season is 148 days across New Hampshire's stations, from 112 days at Berlin Municipal Airport to 180 days at Manchester Airport.

When should I plant tomatoes in New Hampshire?

Plant tomatoes outdoors after your local last frost, ideally after the 10%-risk date when nights stay above 50°F. At a typical New Hampshire station that means starting seeds indoors 6–8 weeks before May 8 and transplanting from about May 22. Check your ZIP code, because dates vary by weeks across the state.

Can it frost in summer in New Hampshire?

Yes, at 1 station in New Hampshire a 32°F night is possible in any month, mostly at high elevation or far north. There is no reliable frost-free season there; use cold-hardy crops and row covers.

How to use these dates

Frost dates are 30-year averages from NOAA, not forecasts. Use them to plan seed starting and planting, then watch the 10-day forecast as the date approaches. Cold air settles in valleys and low spots, so a garden at the bottom of a slope can frost a week or more later in spring than the nearest station shows.

Ready to plan? The planting calendar by ZIP code turns these dates into start-indoors, transplant and sowing dates for 30 crops.

Sources and method

Dates are the 32°F freeze probabilities published in the NOAA NCEI 1991–2020 U.S. Climate Normals for each station. Station names are NOAA's, lightly expanded for readability. See the methodology or download the full table.

Frost dates in other states