Dover, NH frost dates
Last spring frostMay 3median date
First fall frostOct 10median date
Growing season160 daysfrost-free
Hardiness zone6aZone 6a
How Dover compares
- In 8 years out of 10, the last spring frost in Dover falls between April 23 and May 16, a 23-day window. The first fall frost falls between September 27 and October 25.
- The median last frost is 4 days earlier than the New Hampshire median of May 7.
- Its 160-day growing season is longer than 74% of the 252 New Hampshire places with a regular frost season (state median 150 days).
- The last frost is 4 days later than the zone 6a median of Apr 29. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 6a chart.
- The weather station records an average of 150 nights a year at or below 32°F.
- Compared with Haverhill, MA, 50 km away, the last frost here is 2 days later than there and the growing season is 4 days shorter.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 23 |
| 50% (median) | May 3 |
| 10% (safe for tender plants) | May 16 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 27 |
| 50% (median) | October 10 |
| 90% (late) | October 25 |
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 Dover, NH
Dover, NH frost dates — last frost May 3, first frost Oct 10, zone 6a. whenisthelastfrost.com
Crop
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Start indoors: Feb 8 to Feb 22Transplant outside: Apr 5 to Apr 19
Start indoors: Feb 22 to Mar 8Transplant outside: May 17 to May 31
Start indoors: Feb 22 to Mar 8Transplant outside: May 17 to May 31
Start indoors: Mar 8 to Mar 22Transplant outside: May 10 to May 24
Start indoors: Mar 8 to Mar 22Transplant outside: Apr 12 to Apr 26Sow outdoors: Apr 5 to May 10Plant for fall: Aug 15 to Sep 12
Start indoors: Mar 8 to Mar 22Transplant outside: Apr 5 to Apr 19Sow outdoors: Apr 5 to Apr 19Plant for fall: Aug 1 to Aug 22
Start indoors: Mar 8 to Mar 22Transplant outside: Apr 19 to May 3Plant for fall: Jul 4 to Jul 25
Start indoors: Mar 8 to Mar 22Transplant outside: Apr 12 to Apr 26Plant for fall: Jul 4 to Jul 25
Start indoors: Mar 8 to Mar 22Transplant outside: Apr 19 to May 3Plant for fall: Jul 4 to Jul 25
Start indoors: Mar 22 to Apr 5Transplant outside: May 24 to Jun 7Sow outdoors: May 24 to Jun 7
Start indoors: Mar 22 to Apr 5Transplant outside: May 10 to May 24
Sow outdoors: Mar 22 to Apr 12Plant for fall: Jul 18 to Aug 8
Sow outdoors: Mar 22 to Apr 12Plant for fall: Aug 15 to Sep 5
Sow outdoors: Mar 29 to May 10Plant for fall: Aug 29 to Sep 19
Start indoors: Apr 5 to Apr 12Transplant outside: May 17 to May 24Sow outdoors: May 10 to May 24Plant for fall: Jul 25 to Aug 8
Start indoors: Apr 5 to Apr 12Sow outdoors: May 10 to May 24Plant for fall: Aug 1 to Aug 15
Start indoors: Apr 5 to Apr 12Sow outdoors: May 10 to May 24
Start indoors: Apr 5 to Apr 12Transplant outside: May 17 to May 31
Sow outdoors: Apr 12 to May 10Plant for fall: Jul 18 to Aug 1
Sow outdoors: Apr 12 to May 10Plant for fall: Aug 1 to Aug 15
Sow outdoors: Apr 12 to May 3
Sow outdoors: Apr 19 to May 17Plant for fall: Aug 1 to Aug 15
Sow outdoors: Apr 19 to May 10Plant for fall: Aug 15 to Sep 5
Sow outdoors: May 10 to May 31Plant for fall: Jul 25 to Aug 8
Sow outdoors: May 10 to May 24
Transplant outside: May 17 to Jun 7
Plant for fall: Sep 26 to Oct 31
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Dover, NH
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Feb 8 – Feb 22 | Apr 5 – Apr 19 | — | — |
| Peppers | Feb 22 – Mar 8 | May 17 – May 31 | — | — |
| Eggplant | Feb 22 – Mar 8 | May 17 – May 31 | — | — |
| Tomatoes | Mar 8 – Mar 22 | May 10 – May 24 | — | — |
| Lettuce | Mar 8 – Mar 22 | Apr 12 – Apr 26 | Apr 5 – May 10 | Aug 15 – Sep 12 |
| Kale | Mar 8 – Mar 22 | Apr 5 – Apr 19 | Apr 5 – Apr 19 | Aug 1 – Aug 22 |
| Broccoli | Mar 8 – Mar 22 | Apr 19 – May 3 | — | Jul 4 – Jul 25 |
| Cabbage | Mar 8 – Mar 22 | Apr 12 – Apr 26 | — | Jul 4 – Jul 25 |
| Cauliflower | Mar 8 – Mar 22 | Apr 19 – May 3 | — | Jul 4 – Jul 25 |
| Okra | Mar 22 – Apr 5 | May 24 – Jun 7 | May 24 – Jun 7 | — |
| Basil | Mar 22 – Apr 5 | May 10 – May 24 | — | — |
| Peas | — | — | Mar 22 – Apr 12 | Jul 18 – Aug 8 |
| Spinach | — | — | Mar 22 – Apr 12 | Aug 15 – Sep 5 |
| Radishes | — | — | Mar 29 – May 10 | Aug 29 – Sep 19 |
| Cucumbers | Apr 5 – Apr 12 | May 17 – May 24 | May 10 – May 24 | Jul 25 – Aug 8 |
| Zucchini & Summer Squash | Apr 5 – Apr 12 | — | May 10 – May 24 | Aug 1 – Aug 15 |
| Winter Squash & Pumpkins | Apr 5 – Apr 12 | — | May 10 – May 24 | — |
| Melons & Watermelon | Apr 5 – Apr 12 | May 17 – May 31 | — | — |
| Carrots | — | — | Apr 12 – May 10 | Jul 18 – Aug 1 |
| Beets | — | — | Apr 12 – May 10 | Aug 1 – Aug 15 |
| Potatoes | — | — | Apr 12 – May 3 | — |
| Swiss Chard | — | — | Apr 19 – May 17 | Aug 1 – Aug 15 |
| Cilantro | — | — | Apr 19 – May 10 | Aug 15 – Sep 5 |
| Green Beans | — | — | May 10 – May 31 | Jul 25 – Aug 8 |
| Sweet Corn | — | — | May 10 – May 24 | — |
| Sweet Potatoes | — | May 17 – Jun 7 | — | — |
| Garlic | — | — | — | Sep 26 – Oct 31 |
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 Durham 2 N, NH weather station, 5 km away (elevation 118 ft (36 m)).
ZIP codes in Dover: 03820 03821 03822
Frost dates near Dover
- Rollinsford Apr 30 · Oct 9
- Madbury May 3 · Oct 10
- Somersworth Apr 30 · Oct 9
- Durham May 7 · Oct 4
- Lee May 7 · Oct 4
- Barrington May 3 · Oct 10
- Rochester Apr 30 · Oct 9
- Newmarket May 7 · Oct 4
- Portsmouth May 4 · Oct 8
- Greenland May 4 · Oct 8
Frequently asked questions
When is the last frost in Dover, NH?
The median last spring frost in Dover, NH is May 3. There is still about a 10% chance of frost after May 16, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Dover, NH?
The median first fall frost is October 10, with about a 10% chance of frost before September 27.
How long is the growing season in Dover, NH?
About 160 days between the median last spring frost and first fall frost.
What planting zone is Dover, NH?
Dover, NH is in USDA hardiness zone 6a.