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Frost dates for Colebrook 3Sw, NH
NOAA weather station USC00271647 at 1,120 ft elevation. Based on 29 years within 1991-2020. Last verified 2026-10-17.
Last spring freeze (32°F)
May 31
median: freeze still happened after this date in half of years
Jun 4 30% risk · Jun 14 10% risk
First fall freeze (32°F)
Sep 21
median: a freeze had happened by this date in half of years
Sep 7 10% chance of a freeze earlier than this
Freeze-free season
112 days
median length between last spring and first fall 32°F freeze
How to read these dates
Spring: a "10% risk" date means NOAA's 1991-2020 data put the chance of a 32°F or colder night after that date at 10%. The "30% risk" date is the convention used by some popular frost calculators (the Old Farmer's Almanac says it uses a 30% probability threshold, source). Fall: a "10%" date means a 10% chance the first freeze comes before it. Source: NOAA readme.
Full table for this station
| Threshold | Spring: latest-freeze date at risk of 10% / 30% / 50% | Fall: first-freeze date at chance of 10% / 50% |
|---|---|---|
| 36°F (frost possible) | Jul 1 / Jun 17 / Jun 10 | Aug 19 / Sep 7 |
| 32°F (freeze) | Jun 14 / Jun 4 / May 31 | Sep 7 / Sep 21 |
| 28°F (hard freeze) | May 31 / May 22 / May 17 | Sep 20 / Oct 1 |
Also at 32°F, last-freeze 70% date May 25 and 90% date May 16 (frost still likely after these early dates). Data quality: Standard: 24+ years of qualifying data. Source: NOAA NCEI U.S. Climate Normals 1991-2020, station USC00271647, read 2026-10-17.
Is Memorial Day safe here?
Many New England gardeners wait for Memorial Day (it falls between May 25 and May 31). At this station, NOAA's chance of a 32°F or colder night after May 25 is 50-70%, and after May 31 is 30-50%. Your own spot may differ. See all stations.
UNH Extension says that for central New Hampshire, Memorial Day is a conservative estimate of the last frost date (read 2026-10-17).
Your planting schedule
Pick how cautious you want to be. The dates apply UNH Extension's per-crop rules (UNH fact sheet, read 2026-10-17) to this station's last-freeze date. UNH's sheet does not say which probability its "last frost" means, so you choose. These are planning dates, not instructions; follow your seed packet and the weather.
Showing the schedule for the 2027 season (dates repeat yearly). Table below defaults to Typical; it updates when you choose.
| Crop | Start seeds indoors | Outdoors | UNH Extension rule used |
|---|---|---|---|
| Spinach | Mar 12 – Apr 16 | Set out Apr 23 – May 14 | Start 4-6 wk before set-out; set out 3-6 wk before last frost. |
| Broccoli | Mar 26 – Apr 23 | Set out May 7 – May 21 | Start 4-6 wk before set-out; set out 2-4 wk before last frost. |
| Brussels sprout | Mar 26 – Apr 23 | Set out May 7 – May 21 | Start 4-6 wk before set-out; set out 2-4 wk before last frost. |
| Cabbage | Mar 26 – Apr 9 | Set out May 7 | Start 4-6 wk before set-out; set out 4 wk before last frost. |
| Kale | Mar 26 – Apr 9 | Set out May 7 | Start 4-6 wk before set-out; set out 4 wk before last frost. |
| Kohlrabi | Mar 26 – Apr 9 | Set out May 7 | Start 4-6 wk before set-out; set out 4 wk before last frost. |
| Leek | Feb 26 – Mar 12 | Set out May 7 | Start 8-10 wk before set-out; set out 4 wk before last frost. |
| Lettuce | Apr 2 – Apr 16 | Set out May 7 – May 14 | Start 4-5 wk before set-out; set out 3-4 wk before last frost. |
| Onion | Feb 26 – Mar 12 | Set out May 7 | Start 8-10 wk before set-out; set out 4 wk before last frost. |
| Radish | — | Sow May 7 – May 21 | Sow seed in garden 2-4 wk before last frost. |
| Turnip | — | Sow May 7 – May 21 | Sow seed in garden 2-4 wk before last frost. |
| Parsley | Mar 5 – Mar 19 | Set out May 14 – May 21 | Start 9-10 wk before set-out; set out 2-3 wk before last frost. |
| Cauliflower | Apr 9 – Apr 23 | Set out May 21 | Start 4-6 wk before set-out; set out 2 wk before last frost. |
| Potato | — | Sow May 21 – May 28 | Plant seed potatoes 1-2 wk before last frost. |
| Swiss chard | Apr 9 – Apr 23 | Set out May 21; or sow May 7 | Start 4-6 wk before set-out; set out 2 wk before last frost; or sow seed 4 wk before last frost. |
| Bean | — | Sow on/after Jun 4 | Sow seed in garden after last frost. |
| Celery | Mar 12 – Mar 26 | Set out on/after Jun 4 | Start 10-12 wk before set-out; set out after last frost. |
| Parsnip | — | Sow on/after Jun 4 | Sow seed in garden after last frost. |
| Cucumber | May 14 – May 28 | Set out Jun 11 – Jun 18 Direct sow when soil reaches 70°F | Start 3-4 wk before set-out; set out 1-2 wk after last frost; or sow when soil warms to 70°F. |
| Sweet potato | — | Plant slips Jun 11 – Jun 18 | Plant slips (young plants) 1-2 wk after last frost. |
| Tomato | Apr 16 – May 7 | Set out Jun 11 – Jun 18 | Start 6-8 wk before set-out; set out 1-2 wk after last frost. |
| Rutabaga | — | Sow Jun 15 – Jul 15 | Sow seed in garden mid-June to mid-July (fixed dates, not tied to frost). |
| Basil | Apr 23 – May 7 | Set out Jun 18 | Start 6-8 wk before set-out; set out 2 wk after last frost. |
| Eggplant | Apr 9 – Apr 30 | Set out Jun 18 – Jun 25 | Start 8-10 wk before set-out; set out 2-3 wk after last frost. |
| Melon | May 21 – May 28 | Set out Jun 18 | Start 3-4 wk before set-out; set out 2 wk after last frost. |
| Pepper | Apr 9 – Apr 23 | Set out Jun 18 | Start 8-10 wk before set-out; set out 2 wk after last frost. |
| Pumpkin | May 21 – May 28 | Set out Jun 18 Direct sow when soil reaches 70°F | Start 3-4 wk before set-out; set out 2 wk after last frost; or sow when soil warms to 70°F. |
| Summer squash | May 21 – May 28 | Set out Jun 18 Direct sow when soil reaches 70°F | Start 3-4 wk before set-out; set out 2 wk after last frost; or sow when soil warms to 70°F. |
| Winter squash | May 21 – May 28 | Set out Jun 18 Direct sow when soil reaches 70°F | Start 3-4 wk before set-out; set out 2 wk after last frost; or sow when soil warms to 70°F. |
| Zucchini | May 21 – May 28 | Set out Jun 18 Direct sow when soil reaches 70°F | Start 3-4 wk before set-out; set out 2 wk after last frost; or sow when soil warms to 70°F. |
| Beet | — | Sow when soil reaches 45°F (use a soil thermometer) | Sow seed in garden when soil warms to 45°F. |
| Carrot | — | Sow when soil reaches 60°F (use a soil thermometer) | Sow seed in garden when soil warms to 60°F. |
| Corn | — | Sow when soil reaches 60°F (use a soil thermometer) | Sow seed in garden when soil warms to 60°F. |
| Pea | — | Sow as soon as soil thaws | Sow seed in garden as soon as soil thaws. |
Fall: when the garden ends
At this station the median first 32°F freeze is Sep 21; there is a 10% chance of one before Sep 7. Tender crops (tomatoes, peppers, basil) can be damaged at 33-36°F (Almanac.com notes some plants are damaged in that range); the 36°F first-frost date here is median Sep 7 and 10% date Aug 19. UNH Extension notes many fall vegetables tolerate mild frosts down to about 28°F (median first 28°F here: Oct 1), and that row covers can extend the season. UNH: Fall vegetable gardening, read 2026-10-17.
Your garden is not the weather station
This station sits at 1,120 ft. UNH Extension says first-freeze dates vary "even between relatively close locations, based on factors such as elevation" (source), and notes that gardeners who keep garden journals can use their own records. Gardeners on Reddit describe the same thing: elevation and cold spots change when they can plant (for example r/vermont). Treat these dates as a starting point.
Nearby stations
- N Stratford, NH: 13 mi away, 950 ft elevation, median last 32°F freeze May 19
- Island Pond, VT: 18 mi away, 1,200 ft elevation, median last 32°F freeze May 19
- First Connecticut Lake, NH: 20 mi away, 1,650 ft elevation, median last 32°F freeze May 25
- E Haven, VT: 23 mi away, 1,000 ft elevation, median last 32°F freeze May 30
- Lancaster, NH: 25 mi away, 860 ft elevation, median last 32°F freeze May 18