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New Hampshire frost dates

Across 54 NOAA climate stations in New Hampshire, the median last spring frost (32°F) ranges from Apr 21 at Manchester AP to May 31 at Colebrook 3SW; the typical station sees its last frost around May 8 and its first fall frost around Oct 4.

“Median” dates have a 50% chance of a later spring frost or an earlier fall frost. “10% risk” dates are the safer choice for tender plants: only 1 year in 10 has frost beyond them. Source: NOAA NCEI 1991–2020 Climate Normals. Elevation matters: within a state, frost dates can differ by a month or more between valleys and hills.

StationElevationLast frost (median)Last frost (10% risk)First frost (median)First frost (10% risk)Growing season
Benton 5 Sw1,200 ftMay 15Jun 3Sep 28Sep 12133 days
Berlin920 ftMay 14May 30Sep 30Sep 15135 days
Berlin Muni AP1,158 ftMay 30Jun 11Sep 19Sep 5112 days
Bethlehem 21,180 ftMay 24Jun 8Sep 18Sep 6116 days
Bradford 2815 ftMay 15May 29Sep 27Sep 15135 days
Colebrook 3SW1,120 ftMay 31Jun 14Sep 21Sep 7112 days
Concord Muni AP346 ftMay 8May 22Oct 3Sep 21146 days
Durham75 ftMay 8May 22Oct 4Sep 23148 days
Durham 2 N119 ftMay 3May 16Oct 10Sep 27158 days
Durham 2 Ssw63 ftMay 7May 19Oct 4Sep 23150 days
E Milford240 ftApr 28May 12Oct 8Sep 28161 days
E Sandwich692 ftMay 6May 19Oct 6Sep 24151 days
Epping160 ftMay 7May 21Oct 4Sep 22148 days
Errol AP1,240 ftMay 21Jun 3Sep 22Sep 9123 days
First Connecticut Lake1,650 ftMay 25Jun 8Sep 24Sep 9121 days
Franklin Falls Dam450 ftMay 7May 20Oct 3Sep 24148 days
Gorham AP800 ftMay 14May 29Sep 26Sep 11133 days
Grafton830 ftMay 21Jun 5Sep 26Sep 12127 days
Greenland95 ftMay 4May 18Oct 8Sep 27157 days
Greenville 1 Nne900 ftMay 10May 27Oct 6Sep 25147 days
Hanover584 ftMay 1May 15Oct 13Oct 1162 days
Hopkinton Lake430 ftMay 6May 20Oct 1Sep 20146 days
Hudson 1 Sse185 ftMay 3May 16Oct 8Sep 27156 days
Jaffrey Muni AP1,040 ftMay 5May 20Oct 6Sep 25152 days
Jaffrey Silver Rch Airpark1,030 ftMay 5May 19Oct 6Sep 25154 days
Jefferson1,235 ftMay 8May 23Oct 1Sep 16146 days
Keene511 ftMay 14May 28Oct 1Sep 18138 days
Lakeport 2500 ftApr 30May 13Oct 18Oct 4170 days
Lancaster860 ftMay 18Jun 1Sep 30Sep 16132 days
Lebanon Muni AP598 ftMay 9May 24Oct 6Sep 23148 days
Lincoln Nepp807 ftMay 7May 19Oct 4Sep 22149 days
Manchester AP225 ftApr 21May 6Oct 19Oct 4180 days
Massabesic Lake253 ftApr 30May 14Oct 11Sep 30164 days
Meredith 3 Nne861 ftApr 28May 9Oct 16Oct 3171 days
Milford320 ftMay 3May 15Oct 5Sep 25156 days
Mt Sunapee1,275 ftMay 2May 17Oct 9Sep 27158 days
N Conway522 ftMay 7May 19Oct 5Sep 23150 days
N Stratford950 ftMay 19Jun 2Sep 29Sep 15131 days
Nashua 2 Nnw135 ftApr 30May 11Oct 12Sep 30165 days
Nashua Cwsu180 ftApr 29May 11Oct 8Sep 28162 days
Newport770 ftMay 14May 29Oct 1Sep 19140 days
Pinkham Notch2,025 ftMay 18Jun 1Oct 1Sep 15135 days
Plymouth660 ftMay 20Jun 4Sep 27Sep 14128 days
Rochester Skyhaven AP323 ftApr 30May 13Oct 9Sep 27161 days
Salisbury550 ftMay 14May 28Sep 29Sep 14138 days
Tamworth 4541 ftMay 16May 30Sep 26Sep 10129 days
W Hampstead288 ftApr 30May 14Oct 11Sep 29162 days
Walpole 2S Nepp604 ftMay 8May 22Oct 3Sep 22149 days
Waterville Valley Nepp1,429 ftMay 15May 29Sep 28Sep 13134 days
Weare720 ftMay 2May 14Oct 8Sep 27158 days
Weare 2 Ne805 ftMay 9May 23Oct 5Sep 25148 days
Wentworth653 ftMay 12May 25Oct 6Sep 23146 days
Whitefield Mt Washington AP1,074 ftMay 27Jun 10Sep 19Sep 8116 days
York Pond1,519 ftMay 23Jun 6Sep 22Sep 9122 days
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