First & Last Frost Dates in New Hampshire (2026)
Typical first freeze September 25 · last spring frost May 15 · about 135 growing days between them.
Past the typical first-frost date — freeze season is hereWhere New Hampshire sits on the frost line
NOAA 1991 to 2020 normalsCold-air drainage matters here: valley floors like Concord frost earlier than nearby hillsides — the classic New England "frost hollow" effect.
Frost dates for your exact ZIP
The dates above are the state median. Enter a ZIP code to snap to the nearest of 150 NOAA reference stations and read that station’s own first and last freeze instead:
Frost dates across New Hampshire
State averages hide huge local spread — elevation, cold-air drainage, urban heat, and nearby water routinely move frost dates by two to four weeks within the same state. Median dates for representative New Hampshire stations:
| City | Typical first frost | Typical last frost |
|---|---|---|
| Concord | September 24 | May 16 |
| Nashua | October 2 | May 8 |
| Berlin | September 14 | May 26 |
Not near these cities? The ZIP lookup above snaps any US address to its nearest reference station. It is the same tool as the site’s national frost date lookup.
Your New Hampshire first-frost playbook
The New Hampshire planting calendar
Every date below is computed from New Hampshire’s own frost anchors — last frost ~May 15, first frost ~September 25 — using the standard week-count rules seed packets assume. Shift everything a few days for your microclimate (see the city table above).
| Garden task | Typical New Hampshire date | The rule it comes from |
|---|---|---|
| Start onions & leeks indoors | March 6 | ~10 weeks before last frost |
| Start peppers & tomatoes indoors | March 20 | ~8 weeks before last frost |
| Direct-sow peas & spinach | April 10 | ~5 weeks before last frost |
| Plant potatoes | May 1 | ~2 weeks before last frost |
| Transplant tomatoes & peppers out | June 9 | ~1 week after the late frost date |
| Sow fall carrots (70-day) | July 2 | ~12 weeks before first frost |
| Sow fall spinach & lettuce | August 6 | ~7 weeks before first frost |
| Plant garlic | October 9 | ~2 weeks after first frost |
Two rules do most of the work: count backward from first frost for fall crops (a 70-day carrot needs sowing ~12 weeks out, because fall growth slows as days shorten), and count forward from the late last-frost date — not the median — for anything frost-tender going outside.
What dies at what temperature
“Frost” isn’t one event. Surfaces can frost with air temps as high as 36–37°F on calm clear nights; a freeze is 32°F; a hard freeze is 28°F and ends the season for anything unprotected. Crops check out at very different points along the way:
| Crops | Damage point | What it means |
|---|---|---|
| Basil, impatiens, coleus, sweet potato vine | 38–40°F | Damaged before an official frost even hits |
| Tomatoes, peppers, cucumbers, squash, beans | 32°F | Killed by the first light freeze |
| Lettuce, chard, cilantro, peas | 28°F | Shrug off light frost; done at a hard freeze |
| Broccoli, cabbage, carrots, beets | 25°F | Keep producing weeks past first frost |
| Kale, spinach, Brussels sprouts, parsnips | 15–20°F | Frost makes them sweeter — harvest all late fall |
The practical read for New Hampshire: once you’re inside the September 8–October 12 window, the top two rows are living on borrowed time — while the bottom two rows are just getting started. Frost converts starches to sugars in kale, carrots, and parsnips; the sweetest harvests of the year come after first frost.
New Hampshire frost date FAQ
Plan the rest of the season
More Northeast frost dates
Dates are median first/last 32°F freeze approximations from NOAA 1991–2020 climate normals for representative stations, bracketed by roughly the 10%/90% range. Any single year varies; microclimates vary more. National picture: first frost dates for every state