Garden Yardstick

Frost Dates in New Hampshire

Across 54 NOAA weather stations in New Hampshire, the average last spring frost falls between April 21 at Manchester Airport and May 31 at Colebrook 3SW. At a typical New Hampshire station it is around May 8, with the first fall frost around October 4 and a frost-free season of about 148 days.

Find the frost dates for your ZIP code

A typical New Hampshire season

What shapes frost dates in New Hampshire

  • The frost-free season ranges from 112 days at Berlin Muni Airport to 180 days at Manchester Airport.
  • Elevation matters: Pinkham Notch, at 2,025 ft, averages its last frost on May 18, while Durham 2 SSW, at 63 ft, averages May 7.
  • Gardens in valleys and low spots, where cold air settles, often frost a week or more later in spring than the nearest station.

Frost dates at major airports

StationLast frostSafer dateFirst frostSeason (days)
Berlin Muni AirportMay 30Jun 11Sep 19112
Concord Muni AirportMay 8May 22Oct 3146
Durham 2 NMay 3May 16Oct 10158
Durham 2 SSWMay 7May 19Oct 4150
Jaffrey Muni AirportMay 5May 20Oct 6152
Lebanon Muni AirportMay 9May 24Oct 6148
Manchester AirportApr 21May 6Oct 19180
Rochester Skyhaven AirportApr 30May 13Oct 9161
Whitefield Mt Washington AirportMay 27Jun 10Sep 19116

All 54 weather stations in New Hampshire

StationElevation (ft)Last frostSafer dateFirst frostSeason (days)
Benton 5 SW1,200May 15Jun 3Sep 28133
Berlin920May 14May 30Sep 30135
Berlin Muni Airport1,158May 30Jun 11Sep 19112
Bethlehem 21,180May 24Jun 8Sep 18116
Bradford 2815May 15May 29Sep 27135
Colebrook 3SW1,120May 31Jun 14Sep 21112
Concord Muni 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 Muni 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 Muni 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
Mt Sunapee1,275May 2May 17Oct 9158
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 Mt Washington Airport1,074May 27Jun 10Sep 19116
York Pond1,519May 23Jun 6Sep 22122

Last frost and first frost are averages (a 50% chance of frost later in spring or earlier in fall). Safer date is the spring date with only a 10% chance of a later frost.

Using these dates

Plant hardy crops like peas and spinach several weeks before your last frost, and tender crops like tomatoes and peppers after it, once nights stay above 50°F. The Seed Starting Calculator turns your frost date into sowing and planting dates, and When to Plant Tomatoes explains the timing in detail.

Data: NOAA National Centers for Environmental Information, U.S. Climate Normals 1991–2020, 32°F threshold.

Frost dates in other states