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.
| MANCHESTER AP | Apr 21 | May 6 | Apr 8 | Oct 19 | 180 |
| E MILFORD | Apr 28 | May 12 | Apr 18 | Oct 8 | 161 |
| MEREDITH 3 NNE | Apr 28 | May 9 | Apr 15 | Oct 16 | 171 |
| NASHUA CWSU | Apr 29 | May 11 | Apr 16 | Oct 8 | 162 |
| LAKEPORT 2 | Apr 30 | May 13 | Apr 19 | Oct 18 | 170 |
| MASSABESIC LAKE | Apr 30 | May 14 | Apr 19 | Oct 11 | 164 |
| NASHUA 2 NNW | Apr 30 | May 11 | Apr 18 | Oct 12 | 165 |
| ROCHESTER SKYHAVEN AP | Apr 30 | May 13 | Apr 18 | Oct 9 | 161 |
| W HAMPSTEAD | Apr 30 | May 14 | Apr 20 | Oct 11 | 162 |
| HANOVER | May 1 | May 15 | Apr 21 | Oct 13 | 162 |
| MT SUNAPEE | May 2 | May 17 | Apr 21 | Oct 9 | 158 |
| WEARE | May 2 | May 14 | Apr 22 | Oct 8 | 158 |
| DURHAM 2 N | May 3 | May 16 | Apr 23 | Oct 10 | 158 |
| HUDSON 1 SSE | May 3 | May 16 | Apr 24 | Oct 8 | 156 |
| MILFORD | May 3 | May 15 | Apr 22 | Oct 5 | 156 |
| GREENLAND | May 4 | May 18 | Apr 23 | Oct 8 | 157 |
| JAFFREY MUNI AP | May 5 | May 20 | Apr 23 | Oct 6 | 152 |
| JAFFREY SILVER RCH AIRPARK | May 5 | May 19 | Apr 22 | Oct 6 | 154 |
| E SANDWICH | May 6 | May 19 | Apr 26 | Oct 6 | 151 |
| HOPKINTON LAKE | May 6 | May 20 | Apr 27 | Oct 1 | 146 |
| DURHAM 2 SSW | May 7 | May 19 | Apr 25 | Oct 4 | 150 |
| EPPING | May 7 | May 21 | Apr 25 | Oct 4 | 148 |
| FRANKLIN FALLS DAM | May 7 | May 20 | Apr 27 | Oct 3 | 148 |
| LINCOLN NEPP | May 7 | May 19 | Apr 25 | Oct 4 | 149 |
| N CONWAY | May 7 | May 19 | Apr 27 | Oct 5 | 150 |
| CONCORD MUNI AP | May 8 | May 22 | Apr 27 | Oct 3 | 146 |
| DURHAM | May 8 | May 22 | Apr 27 | Oct 4 | 148 |
| JEFFERSON | May 8 | May 23 | Apr 27 | Oct 1 | 146 |
| WALPOLE 2S NEPP | May 8 | May 22 | Apr 24 | Oct 3 | 149 |
| LEBANON MUNI AP | May 9 | May 24 | Apr 27 | Oct 6 | 148 |
| WEARE 2 NE | May 9 | May 23 | Apr 27 | Oct 5 | 148 |
| GREENVILLE 1 NNE | May 10 | May 27 | Apr 26 | Oct 6 | 147 |
| WENTWORTH | May 12 | May 25 | Apr 30 | Oct 6 | 146 |
| BERLIN | May 14 | May 30 | Apr 30 | Sep 30 | 135 |
| GORHAM AP | May 14 | May 29 | May 2 | Sep 26 | 133 |
| KEENE | May 14 | May 28 | Apr 30 | Oct 1 | 138 |
| NEWPORT | May 14 | May 29 | Apr 30 | Oct 1 | 140 |
| SALISBURY | May 14 | May 28 | Apr 30 | Sep 29 | 138 |
| BENTON 5 SW | May 15 | Jun 3 | May 1 | Sep 28 | 133 |
| BRADFORD 2 | May 15 | May 29 | Apr 30 | Sep 27 | 135 |
| WATERVILLE VALLEY NEPP | May 15 | May 29 | May 3 | Sep 28 | 134 |
| TAMWORTH 4 | May 16 | May 30 | May 3 | Sep 26 | 129 |
| LANCASTER | May 18 | Jun 1 | May 3 | Sep 30 | 132 |
| PINKHAM NOTCH | May 18 | Jun 1 | May 3 | Oct 1 | 135 |
| N STRATFORD | May 19 | Jun 2 | May 2 | Sep 29 | 131 |
| PLYMOUTH | May 20 | Jun 4 | May 6 | Sep 27 | 128 |
| ERROL AP | May 21 | Jun 3 | May 7 | Sep 22 | 123 |
| GRAFTON | May 21 | Jun 5 | May 7 | Sep 26 | 127 |
| YORK POND | May 23 | Jun 6 | May 8 | Sep 22 | 122 |
| BETHLEHEM 2 | May 24 | Jun 8 | May 6 | Sep 18 | 116 |
| FIRST CONNECTICUT LAKE | May 25 | Jun 8 | May 9 | Sep 24 | 121 |
| WHITEFIELD MT WASHINGTON AP | May 27 | Jun 10 | May 11 | Sep 19 | 116 |
| BERLIN MUNI AP | May 30 | Jun 11 | May 15 | Sep 19 | 112 |
| COLEBROOK 3SW | May 31 | Jun 14 | May 16 | Sep 21 | 112 |
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 set out frost-tender plants such as dahlia tubers and zinnia seedlings. 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.