Last frost dates in New Hampshire
54 NOAA weather stations in New Hampshire have thirty years of frost records. The median station sees its last 32 °F night around May 8; across the state that ranges from Apr 21 to May 31, so pick the station nearest you rather than a state-wide figure.
| Plan sowing from this date | ||||||
|---|---|---|---|---|---|---|
| MANCHESTER AP | Apr 21 | May 6 | Apr 8 | Oct 19 | 180 | Plan sowing from this date → |
| E MILFORD | Apr 28 | May 12 | Apr 18 | Oct 8 | 161 | Plan sowing from this date → |
| MEREDITH 3 NNE | Apr 28 | May 9 | Apr 15 | Oct 16 | 171 | Plan sowing from this date → |
| NASHUA CWSU | Apr 29 | May 11 | Apr 16 | Oct 8 | 162 | Plan sowing from this date → |
| LAKEPORT 2 | Apr 30 | May 13 | Apr 19 | Oct 18 | 170 | Plan sowing from this date → |
| MASSABESIC LAKE | Apr 30 | May 14 | Apr 19 | Oct 11 | 164 | Plan sowing from this date → |
| NASHUA 2 NNW | Apr 30 | May 11 | Apr 18 | Oct 12 | 165 | Plan sowing from this date → |
| ROCHESTER SKYHAVEN AP | Apr 30 | May 13 | Apr 18 | Oct 9 | 161 | Plan sowing from this date → |
| W HAMPSTEAD | Apr 30 | May 14 | Apr 20 | Oct 11 | 162 | Plan sowing from this date → |
| HANOVER | May 1 | May 15 | Apr 21 | Oct 13 | 162 | Plan sowing from this date → |
| MT SUNAPEE | May 2 | May 17 | Apr 21 | Oct 9 | 158 | Plan sowing from this date → |
| WEARE | May 2 | May 14 | Apr 22 | Oct 8 | 158 | Plan sowing from this date → |
| DURHAM 2 N | May 3 | May 16 | Apr 23 | Oct 10 | 158 | Plan sowing from this date → |
| HUDSON 1 SSE | May 3 | May 16 | Apr 24 | Oct 8 | 156 | Plan sowing from this date → |
| MILFORD | May 3 | May 15 | Apr 22 | Oct 5 | 156 | Plan sowing from this date → |
| GREENLAND | May 4 | May 18 | Apr 23 | Oct 8 | 157 | Plan sowing from this date → |
| JAFFREY MUNI AP | May 5 | May 20 | Apr 23 | Oct 6 | 152 | Plan sowing from this date → |
| JAFFREY SILVER RCH AIRPARK | May 5 | May 19 | Apr 22 | Oct 6 | 154 | Plan sowing from this date → |
| E SANDWICH | May 6 | May 19 | Apr 26 | Oct 6 | 151 | Plan sowing from this date → |
| HOPKINTON LAKE | May 6 | May 20 | Apr 27 | Oct 1 | 146 | Plan sowing from this date → |
| DURHAM 2 SSW | May 7 | May 19 | Apr 25 | Oct 4 | 150 | Plan sowing from this date → |
| EPPING | May 7 | May 21 | Apr 25 | Oct 4 | 148 | Plan sowing from this date → |
| FRANKLIN FALLS DAM | May 7 | May 20 | Apr 27 | Oct 3 | 148 | Plan sowing from this date → |
| LINCOLN NEPP | May 7 | May 19 | Apr 25 | Oct 4 | 149 | Plan sowing from this date → |
| N CONWAY | May 7 | May 19 | Apr 27 | Oct 5 | 150 | Plan sowing from this date → |
| CONCORD MUNI AP | May 8 | May 22 | Apr 27 | Oct 3 | 146 | Plan sowing from this date → |
| DURHAM | May 8 | May 22 | Apr 27 | Oct 4 | 148 | Plan sowing from this date → |
| JEFFERSON | May 8 | May 23 | Apr 27 | Oct 1 | 146 | Plan sowing from this date → |
| WALPOLE 2S NEPP | May 8 | May 22 | Apr 24 | Oct 3 | 149 | Plan sowing from this date → |
| LEBANON MUNI AP | May 9 | May 24 | Apr 27 | Oct 6 | 148 | Plan sowing from this date → |
| WEARE 2 NE | May 9 | May 23 | Apr 27 | Oct 5 | 148 | Plan sowing from this date → |
| GREENVILLE 1 NNE | May 10 | May 27 | Apr 26 | Oct 6 | 147 | Plan sowing from this date → |
| WENTWORTH | May 12 | May 25 | Apr 30 | Oct 6 | 146 | Plan sowing from this date → |
| BERLIN | May 14 | May 30 | Apr 30 | Sep 30 | 135 | Plan sowing from this date → |
| GORHAM AP | May 14 | May 29 | May 2 | Sep 26 | 133 | Plan sowing from this date → |
| KEENE | May 14 | May 28 | Apr 30 | Oct 1 | 138 | Plan sowing from this date → |
| NEWPORT | May 14 | May 29 | Apr 30 | Oct 1 | 140 | Plan sowing from this date → |
| SALISBURY | May 14 | May 28 | Apr 30 | Sep 29 | 138 | Plan sowing from this date → |
| BENTON 5 SW | May 15 | Jun 3 | May 1 | Sep 28 | 133 | Plan sowing from this date → |
| BRADFORD 2 | May 15 | May 29 | Apr 30 | Sep 27 | 135 | Plan sowing from this date → |
| WATERVILLE VALLEY NEPP | May 15 | May 29 | May 3 | Sep 28 | 134 | Plan sowing from this date → |
| TAMWORTH 4 | May 16 | May 30 | May 3 | Sep 26 | 129 | Plan sowing from this date → |
| LANCASTER | May 18 | Jun 1 | May 3 | Sep 30 | 132 | Plan sowing from this date → |
| PINKHAM NOTCH | May 18 | Jun 1 | May 3 | Oct 1 | 135 | Plan sowing from this date → |
| N STRATFORD | May 19 | Jun 2 | May 2 | Sep 29 | 131 | Plan sowing from this date → |
| PLYMOUTH | May 20 | Jun 4 | May 6 | Sep 27 | 128 | Plan sowing from this date → |
| ERROL AP | May 21 | Jun 3 | May 7 | Sep 22 | 123 | Plan sowing from this date → |
| GRAFTON | May 21 | Jun 5 | May 7 | Sep 26 | 127 | Plan sowing from this date → |
| YORK POND | May 23 | Jun 6 | May 8 | Sep 22 | 122 | Plan sowing from this date → |
| BETHLEHEM 2 | May 24 | Jun 8 | May 6 | Sep 18 | 116 | Plan sowing from this date → |
| FIRST CONNECTICUT LAKE | May 25 | Jun 8 | May 9 | Sep 24 | 121 | Plan sowing from this date → |
| WHITEFIELD MT WASHINGTON AP | May 27 | Jun 10 | May 11 | Sep 19 | 116 | Plan sowing from this date → |
| BERLIN MUNI AP | May 30 | Jun 11 | May 15 | Sep 19 | 112 | Plan sowing from this date → |
| COLEBROOK 3SW | May 31 | Jun 14 | May 16 | Sep 21 | 112 | Plan sowing from this date → |
How to read the three dates
Average is the date by which, in half of the years between 1991 and 2020, the last 32 °F night had already happened. Safe is later: only one year in ten saw a frost after it, which is the date to transplant tomatoes and peppers, both killed by a single frost. Early is the risky end, with a frost after it in nine years out of ten.
Every figure is for the weather station, not for your garden. A valley bottom, a north slope or a spot near a lake can run a week or two either way. Cities are warmer than the countryside around them.
Where the numbers come from
The dates are NOAA's U.S. Climate Normals for 1991 to 2020, computed by the National Centers for Environmental Information for every station with thirty years of daily minimum temperatures. ZIP codes are matched to the nearest such station within 150 km using U.S. Census Bureau ZIP Code Tabulation Area centroids. Stations that never see a frost, such as much of south Florida, report no date and are left out.