Frost dates in New Hampshire
Across New Hampshire's 54 NOAA stations with a frost every year, the typical last spring frost ranges from April 21 at Manchester Airport (230 feet above sea level) to May 31 at Colebrook 3 SW (1,120 feet above sea level). The middle station's date is May 8.
Look up your ZIP code
Last frost across New Hampshire
The frost-free season runs from 112 days at Colebrook 3 SW to 180 days at Manchester Airport.
At 1 station, all high or far north, frost is possible in every month.
These are typical dates: in half of springs the last frost comes later. Each place's page, and each ZIP code lookup, also gives the late-year date, after which only 1 spring in 10 has a frost. That's the safer date for tender plants.
Frost dates for New Hampshire's larger places
| Place | Last spring frost | First fall frost | Season | Zone |
|---|---|---|---|---|
| Concord | May 8 | October 3 | 146 days | 5b |
| Manchester | April 21 | October 19 | 180 days | 6a |
| Nashua | April 30 | October 12 | 165 days | 6a |
Typical (1-in-2) dates. Each place's page has the early and late years, a planting calendar and a printable planner. Zones are for the ZIP code nearest each place's center.
Hardiness zones in New Hampshire
New Hampshire's 279 ZIP codes in the USDA list fall in zones 4a to 6b: 4a (2 percent), 4b (3 percent), 5a (21 percent), 5b (30 percent), 6a (43 percent) and 6b (1 percent). Compared with the 2012 map, 57 percent of them moved to a warmer half zone (3 by a full zone or more), 41 percent stayed the same and 4 moved to a colder one.
A hardiness zone is about the coldest night of winter, which decides which shrubs, trees and perennials survive. Frost dates are about spring and fall, which decide when to plant. You need both. Read more about what the zones mean and what changed in 2023.
Every NOAA station in New Hampshire
All 55 stations in New Hampshire with frost statistics in NOAA's 1991 to 2020 normals, from A to Z. Station names are usually a town, an airport, or a distance and direction from a town. Find one near you and at a similar elevation.
| Station | Elevation (feet) | Last spring frost | First fall frost | Season (days) |
|---|---|---|---|---|
| Benton 5 SW | 1,200 | May 15 | September 28 | 133 |
| Berlin | 920 | May 14 | September 30 | 135 |
| Berlin Municipal Airport | 1,160 | May 30 | September 19 | 112 |
| Bethlehem 2 | 1,180 | May 24 | September 18 | 116 |
| Bradford 2 | 810 | May 15 | September 27 | 135 |
| Colebrook 3 SW | 1,120 | May 31 | September 21 | 112 |
| Concord Municipal Airport | 350 | May 8 | October 3 | 146 |
| Durham | 80 | May 8 | October 4 | 148 |
| Durham 2 N | 120 | May 3 | October 10 | 158 |
| Durham 2 SSW | 60 | May 7 | October 4 | 150 |
| E Milford | 240 | April 28 | October 8 | 161 |
| E Sandwich | 690 | May 6 | October 6 | 151 |
| Epping | 160 | May 7 | October 4 | 148 |
| Errol Airport | 1,240 | May 21 | September 22 | 123 |
| First Connecticut Lake | 1,650 | May 25 | September 24 | 121 |
| Franklin Falls Dam | 450 | May 7 | October 3 | 148 |
| Gorham Airport | 800 | May 14 | September 26 | 133 |
| Grafton | 830 | May 21 | September 26 | 127 |
| Greenland | 100 | May 4 | October 8 | 157 |
| Greenville 1 NNE | 900 | May 10 | October 6 | 147 |
| Hanover | 580 | May 1 | October 13 | 162 |
| Hopkinton Lake | 430 | May 6 | October 1 | 146 |
| Hudson 1 SSE | 180 | May 3 | October 8 | 156 |
| Jaffrey Municipal Airport | 1,040 | May 5 | October 6 | 152 |
| Jaffrey Silver Ranch Airpark | 1,030 | May 5 | October 6 | 154 |
| Jefferson | 1,230 | May 8 | October 1 | 146 |
| Keene | 510 | May 14 | October 1 | 138 |
| Lakeport 2 | 500 | April 30 | October 18 | 170 |
| Lancaster | 860 | May 18 | September 30 | 132 |
| Lebanon Municipal Airport | 600 | May 9 | October 6 | 148 |
| Lincoln Nepp | 810 | May 7 | October 4 | 149 |
| Manchester Airport | 230 | April 21 | October 19 | 180 |
| Massabesic Lake | 250 | April 30 | October 11 | 164 |
| Meredith 3 NNE | 860 | April 28 | October 16 | 171 |
| Milford | 320 | May 3 | October 5 | 156 |
| Mount Sunapee | 1,280 | May 2 | October 9 | 158 |
| Mount Washington | 6,270 | Frost possible any month | 66 | |
| N Conway | 520 | May 7 | October 5 | 150 |
| N Stratford | 950 | May 19 | September 29 | 131 |
| Nashua 2 NNW | 130 | April 30 | October 12 | 165 |
| Nashua Cwsu | 180 | April 29 | October 8 | 162 |
| Newport | 770 | May 14 | October 1 | 140 |
| Pinkham Notch | 2,020 | May 18 | October 1 | 135 |
| Plymouth | 660 | May 20 | September 27 | 128 |
| Rochester Skyhaven Airport | 320 | April 30 | October 9 | 161 |
| Salisbury | 550 | May 14 | September 29 | 138 |
| Tamworth 4 | 540 | May 16 | September 26 | 129 |
| W Hampstead | 290 | April 30 | October 11 | 162 |
| Walpole 2 S Nepp | 600 | May 8 | October 3 | 149 |
| Waterville Valley Nepp | 1,430 | May 15 | September 28 | 134 |
| Weare | 720 | May 2 | October 8 | 158 |
| Weare 2 NE | 800 | May 9 | October 5 | 148 |
| Wentworth | 650 | May 12 | October 6 | 146 |
| Whitefield Mount Washington Airport | 1,070 | May 27 | September 19 | 116 |
| York Pond | 1,520 | May 23 | September 22 | 122 |
Typical (1-in-2) dates at 32°F. For the early and late years, and a planting calendar built from your own dates, look up your ZIP code.