New Hampshire frost dates: Last spring and first autumn frost at every NOAA station, 1991-2020
Across New Hampshire's 54 NOAA stations with frost dates, the median last spring frost (32°F) runs from April 21 in Manchester to May 31 in Colebrook; for half of its places it comes after May 8.
- Typical last spring frost
- May 8median of 28 places
- Typical first autumn frost
- October 4median of 28 places
- Earliest last frost
- April 21Manchester
- Latest last frost
- May 31Colebrook
When is the last frost in New Hampshire, town by town?
Each date is NOAA's: "after May 8 in half of years" means the last 32°F night of spring came after May 8 in half of the years 1991-2020. By the 1-in-10 date, the last frost has passed in nine years out of ten.
Find your town in the list, or look up a ZIP code for the stations nearest it.
| Place or station | Last frost (median) | 1 in 10 after | First frost (median) | 1 in 10 before | Growing season | Zone |
|---|---|---|---|---|---|---|
| ManchesterManchester Airport | April 21 | May 6 | October 19 | October 4 | 180 days | 6b |
| East Milford | April 28 | May 12 | October 8 | September 28 | 161 days | – |
| Meredith3 mi NNE | April 28 | May 9 | October 16 | October 3 | 171 days | – |
| NashuaNashua Cwsu | April 29 | May 11 | October 8 | September 28 | 162 days | – |
| LaconiaLakeport 2 | April 30 | May 13 | October 18 | October 4 | 170 days | 6a |
| Massabesic Lake | April 30 | May 14 | October 11 | September 30 | 164 days | 5b |
| Nashua (2 mi NNW) | April 30 | May 11 | October 12 | September 30 | 165 days | 6a |
| RochesterRochester Skyhaven Airport | April 30 | May 13 | October 9 | September 27 | 161 days | 6a |
| West Hampstead | April 30 | May 14 | October 11 | September 29 | 162 days | 6a |
| Hanover | May 1 | May 15 | October 13 | October 1 | 162 days | 5a |
| Mount Sunapee | May 2 | May 17 | October 9 | September 27 | 158 days | 6a |
| Weare | May 2 | May 14 | October 8 | September 27 | 158 days | – |
| Durham2 mi N | May 3 | May 16 | October 10 | September 27 | 158 days | 6a |
| Hudson1 mi SSE | May 3 | May 16 | October 8 | September 27 | 156 days | 5b |
| Milford | May 3 | May 15 | October 5 | September 25 | 156 days | – |
| Greenland | May 4 | May 18 | October 8 | September 27 | 157 days | 6a |
| JaffreyJaffrey Municipal Airport | May 5 | May 20 | October 6 | September 25 | 152 days | 5b |
| Jaffrey Silver Ranch Airpark | May 5 | May 19 | October 6 | September 25 | 154 days | – |
| East Sandwich | May 6 | May 19 | October 6 | September 24 | 151 days | – |
| Hopkinton Lake | May 6 | May 20 | October 1 | September 20 | 146 days | – |
| Durham (2 mi SSW) | May 7 | May 19 | October 4 | September 23 | 150 days | – |
| Epping | May 7 | May 21 | October 4 | September 22 | 148 days | 6a |
| FranklinFranklin Falls Dam | May 7 | May 20 | October 3 | September 24 | 148 days | – |
| LincolnLincoln Nepp | May 7 | May 19 | October 4 | September 22 | 149 days | – |
| North Conway | May 7 | May 19 | October 5 | September 23 | 150 days | 5b |
| ConcordConcord Municipal Airport | May 8 | May 22 | October 3 | September 21 | 146 days | 5b |
| Durham station | May 8 | May 22 | October 4 | September 23 | 148 days | – |
| Jefferson | May 8 | May 23 | October 1 | September 16 | 146 days | – |
| WalpoleWalpole 2 mi S Nepp | May 8 | May 22 | October 3 | September 22 | 149 days | – |
| LebanonLebanon Municipal Airport | May 9 | May 24 | October 6 | September 23 | 148 days | 5a |
| Weare (2 mi NE) | May 9 | May 23 | October 5 | September 25 | 148 days | – |
| Greenville1 mi NNE | May 10 | May 27 | October 6 | September 25 | 147 days | – |
| Wentworth | May 12 | May 25 | October 6 | September 23 | 146 days | – |
| Berlin station | May 14 | May 30 | September 30 | September 15 | 135 days | 5a |
| GorhamGorham Airport | May 14 | May 29 | September 26 | September 11 | 133 days | – |
| Keene | May 14 | May 28 | October 1 | September 18 | 138 days | 5b |
| Newport | May 14 | May 29 | October 1 | September 19 | 140 days | 5a |
| Salisbury | May 14 | May 28 | September 29 | September 14 | 138 days | 6a |
| Benton (5 mi SW) | May 15 | June 3 | September 28 | September 12 | 133 days | 5a |
| BradfordBradford 2 | May 15 | May 29 | September 27 | September 15 | 135 days | 5b |
| Waterville Valley Nepp | May 15 | May 29 | September 28 | September 13 | 134 days | – |
| Tamworth 4 | May 16 | May 30 | September 26 | September 10 | 129 days | 5a |
| Lancaster | May 18 | June 1 | September 30 | September 16 | 132 days | 4a |
| Pinkham Notch | May 18 | June 1 | October 1 | September 15 | 135 days | 5a |
| North Stratford | May 19 | June 2 | September 29 | September 15 | 131 days | 4a |
| Plymouth | May 20 | June 4 | September 27 | September 14 | 128 days | 5a |
| Errol Airport | May 21 | June 3 | September 22 | September 9 | 123 days | – |
| Grafton | May 21 | June 5 | September 26 | September 12 | 127 days | – |
| York Pond | May 23 | June 6 | September 22 | September 9 | 122 days | 4b |
| BethlehemBethlehem 2 | May 24 | June 8 | September 18 | September 6 | 116 days | 4b |
| First Connecticut Lake | May 25 | June 8 | September 24 | September 9 | 121 days | 3b |
| WhitefieldWhitefield Mount Washington Airport | May 27 | June 10 | September 19 | September 8 | 116 days | 4a |
| BerlinBerlin Municipal Airport | May 30 | June 11 | September 19 | September 5 | 112 days | 4a |
| Colebrook3 mi SW | May 31 | June 14 | September 21 | September 7 | 112 days | 4a |
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities, growing-season length); station daily lows via ACIS (zone). Growing season: NOAA's median number of days between the last spring and first autumn 32°F night. Zone: the USDA's plant hardiness rule applied to the station's own 1991-2020 coldest nights.