New Hampshire Planting Zones
New Hampshire runs from zone 4a to zone 6b on the 2023 USDA map. Zone 6a is the most common, covering 43% of the state's ZIP codes. Manchester is 6a, Portsmouth is 6a and Concord is 5b.
Zones across New Hampshire
| Zone | Average coldest night | Share of New Hampshire ZIP codes |
|---|---|---|
| 4a | −30 to −25°F | 2% |
| 4b | −25 to −20°F | 3% |
| 5a | −20 to −15°F | 21% |
| 5b | −15 to −10°F | 30% |
| 6a | −10 to −5°F | 43% |
| 6b | −5 to 0°F | under 1% |
Planting zone for every city and town in New Hampshire
Each New Hampshire town uses the ZIP code at its center. Big towns can cross into the next half-zone, so look up your own ZIP if you're near a line.
| City | Zone | Average coldest night |
|---|---|---|
| Berlin | 4b | −25 to −20°F |
| Claremont | 5b | −15 to −10°F |
| Concord | 5b | −15 to −10°F |
| Dover | 6a | −10 to −5°F |
| Franklin | 5b | −15 to −10°F |
| Keene | 5b | −15 to −10°F |
| Laconia | 5b | −15 to −10°F |
| Lebanon | 5a | −20 to −15°F |
| Manchester | 6a | −10 to −5°F |
| Nashua | 6a | −10 to −5°F |
| Portsmouth | 6a | −10 to −5°F |
| Rochester | 6a | −10 to −5°F |
| Somersworth | 6a | −10 to −5°F |
Source: USDA Plant Hardiness Zone Map, 2023, Agricultural Research Service, U.S. Department of Agriculture; ZIP code table from the PRISM Group, Oregon State University (accessed Oct 2026). This list is our own summary, not the official USDA map. See how we calculate.
Frequently asked questions
What planting zone is New Hampshire?
New Hampshire spans zones 4a to 6b on the 2023 USDA map, and zone 6a is the most common. Look up your ZIP code for your exact zone.
What zone is Manchester, NH?
Manchester is zone 6a, where the coldest night of an average winter falls from −10 to −5°F. Plants rated hardy to zone 6 or colder should survive a typical winter there.
More for New Hampshire: New Hampshire climate zones (insulation) · Last frost dates in New Hampshire · Frost line depth by state