Colebrook, NH frost dates
Last spring frostMay 31median date
First fall frostSep 21median date
Growing season113 daysfrost-free
Hardiness zone4aZone 4a
How Colebrook compares
- In 8 years out of 10, the last spring frost in Colebrook falls between May 16 and June 14, a 29-day window. The first fall frost falls between September 7 and October 2.
- The median last frost is 24 days later than the New Hampshire median of May 7.
- Its 113-day growing season is among the shortest of the 252 New Hampshire places with a regular frost season.
- The last frost is 19 days later than the zone 4a median of May 12. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 4a chart.
- The weather station records an average of 191 nights a year at or below 32°F.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | May 16 |
| 50% (median) | May 31 |
| 10% (safe for tender plants) | June 14 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 7 |
| 50% (median) | September 21 |
| 90% (late) | October 2 |
Frost here means 32°F (0°C). A median date means half of years have their last frost earlier and half later.
Planting calendar for Colebrook, NH
Colebrook, NH frost dates — last frost May 31, first frost Sep 21, zone 4a. whenisthelastfrost.com
Crop
JFMAMJJASOND
Start indoors: Mar 8 to Mar 22Transplant outside: May 3 to May 17
Start indoors: Mar 22 to Apr 5Transplant outside: Jun 14 to Jun 28
Start indoors: Mar 22 to Apr 5Transplant outside: Jun 14 to Jun 28
Start indoors: Apr 5 to Apr 19Transplant outside: Jun 7 to Jun 21
Start indoors: Apr 5 to Apr 19Transplant outside: May 10 to May 24Sow outdoors: May 3 to Jun 7Plant for fall: Jul 27 to Aug 24
Start indoors: Apr 5 to Apr 19Transplant outside: May 3 to May 17Sow outdoors: May 3 to May 17Plant for fall: Jul 13 to Aug 3
Start indoors: Apr 5 to Apr 19Transplant outside: May 17 to May 31Plant for fall: Jun 15 to Jul 6
Start indoors: Apr 5 to Apr 19Transplant outside: May 10 to May 24Plant for fall: Jun 15 to Jul 6
Start indoors: Apr 5 to Apr 19Transplant outside: May 17 to May 31Plant for fall: Jun 15 to Jul 6
Start indoors: Apr 19 to May 3Transplant outside: Jun 21 to Jul 5Sow outdoors: Jun 21 to Jul 5
Start indoors: Apr 19 to May 3Transplant outside: Jun 7 to Jun 21
Sow outdoors: Apr 19 to May 10Plant for fall: Jun 29 to Jul 20
Sow outdoors: Apr 19 to May 10Plant for fall: Jul 27 to Aug 17
Sow outdoors: Apr 26 to Jun 7Plant for fall: Aug 10 to Aug 31
Start indoors: May 3 to May 10Transplant outside: Jun 14 to Jun 21Sow outdoors: Jun 7 to Jun 21Plant for fall: Jul 6 to Jul 20
Start indoors: May 3 to May 10Sow outdoors: Jun 7 to Jun 21Plant for fall: Jul 13 to Jul 27
Start indoors: May 3 to May 10Sow outdoors: Jun 7 to Jun 21
Start indoors: May 3 to May 10Transplant outside: Jun 14 to Jun 28
Sow outdoors: May 10 to Jun 7Plant for fall: Jun 29 to Jul 13
Sow outdoors: May 10 to Jun 7Plant for fall: Jul 13 to Jul 27
Sow outdoors: May 10 to May 31
Sow outdoors: May 17 to Jun 14Plant for fall: Jul 13 to Jul 27
Sow outdoors: May 17 to Jun 7Plant for fall: Jul 27 to Aug 17
Sow outdoors: Jun 7 to Jun 28
Sow outdoors: Jun 7 to Jun 21
Transplant outside: Jun 14 to Jul 5
Plant for fall: Sep 7 to Oct 12
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Colebrook, NH
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Mar 8 – Mar 22 | May 3 – May 17 | — | — |
| Peppers | Mar 22 – Apr 5 | Jun 14 – Jun 28 | — | — |
| Eggplant | Mar 22 – Apr 5 | Jun 14 – Jun 28 | — | — |
| Tomatoes | Apr 5 – Apr 19 | Jun 7 – Jun 21 | — | — |
| Lettuce | Apr 5 – Apr 19 | May 10 – May 24 | May 3 – Jun 7 | Jul 27 – Aug 24 |
| Kale | Apr 5 – Apr 19 | May 3 – May 17 | May 3 – May 17 | Jul 13 – Aug 3 |
| Broccoli | Apr 5 – Apr 19 | May 17 – May 31 | — | Jun 15 – Jul 6 |
| Cabbage | Apr 5 – Apr 19 | May 10 – May 24 | — | Jun 15 – Jul 6 |
| Cauliflower | Apr 5 – Apr 19 | May 17 – May 31 | — | Jun 15 – Jul 6 |
| Okra | Apr 19 – May 3 | Jun 21 – Jul 5 | Jun 21 – Jul 5 | — |
| Basil | Apr 19 – May 3 | Jun 7 – Jun 21 | — | — |
| Peas | — | — | Apr 19 – May 10 | Jun 29 – Jul 20 |
| Spinach | — | — | Apr 19 – May 10 | Jul 27 – Aug 17 |
| Radishes | — | — | Apr 26 – Jun 7 | Aug 10 – Aug 31 |
| Cucumbers | May 3 – May 10 | Jun 14 – Jun 21 | Jun 7 – Jun 21 | Jul 6 – Jul 20 |
| Zucchini & Summer Squash | May 3 – May 10 | — | Jun 7 – Jun 21 | Jul 13 – Jul 27 |
| Winter Squash & Pumpkins Warning: Your frost-free season is about 113 days, which is tight for winter squash & pumpkins (100+ days). Choose early varieties and use transplants or row covers. | May 3 – May 10 | — | Jun 7 – Jun 21 | — |
| Melons & Watermelon | May 3 – May 10 | Jun 14 – Jun 28 | — | — |
| Carrots | — | — | May 10 – Jun 7 | Jun 29 – Jul 13 |
| Beets | — | — | May 10 – Jun 7 | Jul 13 – Jul 27 |
| Potatoes | — | — | May 10 – May 31 | — |
| Swiss Chard | — | — | May 17 – Jun 14 | Jul 13 – Jul 27 |
| Cilantro | — | — | May 17 – Jun 7 | Jul 27 – Aug 17 |
| Green Beans | — | — | Jun 7 – Jun 28 | — |
| Sweet Corn | — | — | Jun 7 – Jun 21 | — |
| Sweet Potatoes Warning: Your frost-free season is about 113 days, which is tight for sweet potatoes (100+ days). Choose early varieties and use transplants or row covers. | — | Jun 14 – Jul 5 | — | — |
| Garlic | — | — | — | Sep 7 – Oct 12 |
Dates come from the median frost dates and common extension-service timing. Adjust for your soil temperature, microclimate and the varieties you grow.
About these dates
Based on 1991–2020 NOAA climate normals for the Colebrook 3sw, NH weather station, 7 km away (elevation 1,119 ft (341 m)).
Frost dates near Colebrook
- Pittsburg May 25 · Sep 24
- North Stratford May 19 · Sep 29
- Mount Washington May 19 · Sep 29
- West Stewartstown May 19 · Sep 29
- Errol May 21 · Sep 22
- Groveton May 19 · Sep 29
- Milan May 30 · Sep 19
- Lancaster May 18 · Sep 30
- Berlin May 14 · Sep 30
- Jefferson May 8 · Oct 1
Frequently asked questions
When is the last frost in Colebrook, NH?
The median last spring frost in Colebrook, NH is May 31. There is still about a 10% chance of frost after June 14, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Colebrook, NH?
The median first fall frost is September 21, with about a 10% chance of frost before September 7.
How long is the growing season in Colebrook, NH?
About 113 days between the median last spring frost and first fall frost.
What planting zone is Colebrook, NH?
Colebrook, NH is in USDA hardiness zone 4a.