New Hampshire Frost Dates
Across New Hampshire's 13 cities and towns, the average last spring frost runs from April 29 in Nashua to May 14 in Keene. Average last frost elsewhere: Manchester Apr 30, Portsmouth May 4 and Concord May 8.
Frost dates for every city and town in New Hampshire
Dates are for 32°F at the NOAA station nearest the ZIP code at each New Hampshire town's center. "Safer date" is when only 1 year in 10 still gets a frost, a good target for tomatoes and peppers.
| City | Average last frost | Safer date | Average first frost | Frost-free days |
|---|---|---|---|---|
| Berlin | May 14 | May 30 | Sep 30 | 139 |
| Claremont | May 14 | May 29 | Oct 1 | 140 |
| Concord | May 8 | May 22 | Oct 3 | 148 |
| Dover | May 3 | May 16 | Oct 10 | 160 |
| Franklin | May 7 | May 20 | Oct 3 | 149 |
| Keene | May 14 | May 28 | Oct 1 | 140 |
| Laconia | Apr 30 | May 13 | Oct 18 | 171 |
| Lebanon | May 9 | May 24 | Oct 6 | 150 |
| Manchester | Apr 30 | May 14 | Oct 11 | 164 |
| Nashua | Apr 29 | May 11 | Oct 8 | 162 |
| Portsmouth | May 4 | May 18 | Oct 8 | 157 |
| Rochester | Apr 30 | May 13 | Oct 9 | 162 |
| Somersworth | Apr 30 | May 13 | Oct 9 | 162 |
Source: NOAA National Centers for Environmental Information, U.S. Climate Normals 1991–2020. City centers from the US Census Bureau. Click a city for its nearest station and, where it has frost dates, hard-freeze dates and a vegetable planting calendar. See how we calculate.
Frequently asked questions
When is the last frost in Manchester, NH?
The average last spring frost in Manchester is April 30, and only 1 year in 10 has a frost after May 14. The average first fall frost is October 11. These come from NOAA's 1991–2020 records at the Massabesic Lake station.
When should I plant tomatoes in New Hampshire?
UNH Extension times tomato transplants for 1 to 2 weeks after the average last frost. In Manchester that's about May 7 to May 14. Look up your ZIP code for your own dates and a full vegetable planting calendar.
More for New Hampshire: New Hampshire climate zones (insulation) · New Hampshire planting zones · Frost line depth by state