Frost dates by state › New Hampshire
New Hampshire frost dates
Average last spring and first fall frost dates for New Hampshire’s largest cities, with each city’s USDA hardiness zone.
Reviewed October 2026
Among New Hampshire’s 13 largest cities, the average last spring frost ranges from Apr 29 in Nashua to May 23 in Berlin. Elevation, distance from the coast and city heat all shift the date, so use your own ZIP code below for the closest match.
| City | Average last spring frost | Average first fall frost | Frost-free days | Hardiness zone | Weather station used |
|---|---|---|---|---|---|
| Manchester | Apr 30 | Oct 11 | 164 | 6a | Massabesic Lake, NH, 3 mi |
| Nashua | Apr 29 | Oct 8 | 162 | 6a | Nashua Cwsu, NH |
| Concord | May 8 | Oct 3 | 148 | 5b | Concord Muni Airport, NH, 4 mi |
| Dover | May 3 | Oct 10 | 160 | 6a | Durham 2 N, NH, 2 mi |
| Rochester | Apr 30 | Oct 9 | 162 | 6a | Rochester Skyhaven Airport, NH, 3 mi |
| Keene | May 14 | Oct 1 | 140 | 5b–6a | Keene, NH |
| Portsmouth | May 4 | Oct 8 | 157 | 6a | Greenland, NH, 4 mi |
| Laconia | Apr 30 | Oct 18 | 171 | 5b | Lakeport 2, NH, 2 mi |
| Lebanon | May 9 | Oct 6 | 150 | 5a | Lebanon Muni Airport, NH, 3 mi |
| Claremont | May 14 | Oct 1 | 140 | 5b | Newport, NH, 8 mi |
| Somersworth | Apr 30 | Oct 9 | 162 | 6a | Rochester Skyhaven Airport, NH, 2 mi |
| Berlin | May 23 | Sep 22 | 122 | 4b | York Pond, NH, 3 mi |
| Franklin | May 7 | Oct 3 | 149 | 5b | Franklin Falls Dam, NH |
Frost dates are the dates after (spring) or before (fall) which the chance of a 32°F freeze is below 50%, from NOAA’s 1991–2020 U.S. Climate Normals for the weather station nearest each city’s center. Zones are from the 2023 USDA Plant Hardiness Zone Map for the ZIP codes around each city; a range means nearby ZIP codes differ. Cities are the 13 largest by Census Bureau 2024 population estimates.
An average is not a guarantee. There’s still about a 1 in 2 chance of frost after the average last spring date. Many gardeners wait an extra week or two before setting out tomatoes, peppers and basil, and keep covers handy.
Planting dates for Manchester
Timed from Manchester’s average last frost of Apr 30, using University of New Hampshire Extension’s planting guidance. For your exact dates, enter your ZIP code in the calendar below.
| Crop | Start seeds indoors | Plant outside |
|---|---|---|
| Tomatoes | Mar 12 to Mar 26 | May 7 to May 14 |
| Peppers | Mar 5 to Mar 19 | May 14 |
| Lettuce | Feb 26 to Mar 5 | Apr 2 to Apr 9 |
| Broccoli | Feb 19 to Mar 5 | Apr 2 to Apr 16 |
| Cucumbers | Apr 9 to Apr 16 | May 7 to May 14 |
| Basil | Mar 19 to Apr 2 | May 14 |
When to plant, for your garden
Your seed-starting and planting dates, timed from your last spring frost. Full calendar, 12 crops.
Enter your ZIP code to look up your average last frost date and hardiness zone, or type the date in yourself.
Frost dates: NOAA U.S. Climate Normals, 1991–2020. Hardiness zones: USDA Plant Hardiness Zone Map, 2023, ZIP code data from PRISM Group, Oregon State University, prism.oregonstate.edu, accessed Oct. 20, 2026.
More about frost dates
How to find your last frost date, and what your zone means · Full planting calendar · How to start seeds indoors
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