In New Hampshire, the last spring frost usually comes between May 4 and May 26, and the first fall frost between September 19 and October 6, depending on where you live. Most of New Hampshire is in USDA hardiness zones 4b to 6a.
Find the frost dates for your ZIP code
Frost dates from NOAA 1991–2020 U.S. Climate Normals, nearest weather station. Zones derived from the 2023 USDA Plant Hardiness Zone Map data (PRISM Climate Group, Oregon State University). This is not the official USDA Plant Hardiness Zone Map.
Frost dates for New Hampshire cities
Dates come from the NOAA weather station closest to each city. The last spring frost and first fall frost are the typical dates, with a 30% chance of frost after (or before) them. The safer planting date has only a 10% chance of a later spring frost: use it for tender plants like tomatoes, peppers and basil.
| City | Zone | Last frost | Safer date | First frost |
|---|---|---|---|---|
| Manchester | 6a | May 4 | May 14 | Oct. 6 |
| Nashua | 6a | May 4 | May 11 | Oct. 5 |
| Concord | 5b | May 15 | May 22 | Sep. 29 |
| Dover | 6a | May 8 | May 16 | Oct. 4 |
| Salem | 6a | April 19 | April 29 | Oct. 22 |
| Keene | 5b | May 19 | May 28 | Sep. 26 |
| Laconia | 5b | May 4 | May 13 | Oct. 12 |
| Lebanon | 5a | May 16 | May 24 | Oct. 1 |
| Claremont | 5b | May 20 | May 29 | Sep. 27 |
Frost dates vary a lot across New Hampshire. Among the cities above, Salem has the earliest last frost (around April 19) and Claremont the latest (around May 20), about 4 weeks apart. Elevation, nearby water and local terrain all make a difference, so use the dates for the place closest to you, or look up your ZIP code.
Growing zones in New Hampshire
Most of New Hampshire is in USDA hardiness zones 4b to 6a. A typical frost-free growing season lasts about 155 days, longer in the warmest areas and shorter in the coldest.
Find planting dates for the main zones in New Hampshire:
- Zone 4 (about 9% of ZIP codes): Tomatoes, Peppers, Potatoes, Lettuce, Green beans, Cucumbers, Garlic, Tulips
- Zone 5 (about 52% of ZIP codes): Tomatoes, Peppers, Potatoes, Lettuce, Green beans, Cucumbers, Garlic, Tulips
- Zone 6 (about 39% of ZIP codes): Tomatoes, Peppers, Potatoes, Lettuce, Green beans, Cucumbers, Garlic, Tulips
See all crops in our planting guides, or build a planting calendar for your ZIP code.
How to use frost dates
- Cool-season crops such as peas, lettuce, spinach and onions can go in several weeks before your last spring frost.
- Warm-season crops such as tomatoes, peppers, squash and beans wait until after it, when the soil has warmed.
- Fall crops are timed back from your first fall frost, and garlic and tulips are planted around it.
- Frost dates are averages. Check the forecast before setting out tender plants.
Frequently asked questions
When is the last frost in New Hampshire?
It depends on where you live. Across most of New Hampshire, the last spring frost comes between May 4 and May 26. In Manchester, it is around May 4.
When is the first frost in New Hampshire?
Across most of New Hampshire, the first fall frost comes between September 19 and October 6. In Manchester, it is around October 6.
What planting zone is New Hampshire?
Most of New Hampshire is in USDA hardiness zones 4b to 6a. Enter your ZIP code above to find your exact zone.
When can I plant tomatoes in New Hampshire?
Plant tomatoes outside after your last frost, once nights stay above 50 °F. In Manchester, the safer date, with only a 10% chance of a later frost, is around May 14. See when to plant tomatoes in zone 6.
Sources. Frost dates come from the nearest NOAA weather station to each city or ZIP code. Zones come from the 2023 USDA Plant Hardiness Zone Map ZIP code data. Our zone lookup is not the official USDA map.