Frost dates for 03822Dover, NH
The average last spring frost in Dover is May 3 and the average first fall frost is October 10, giving a typical growing season of about 158 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 3
- Average first fall frost
- Oct 10
- Growing season
- 158 days
Safer after May 16 (1-in-10 risk)
Possible by Sep 27 (1-in-10 risk)
Last frost typically in 183 days
Frost risk by date
NOAA reports frost dates as probabilities. The middle date is the average (a 50% chance). For spring, the 10% date is a safer planting date: frost after it happens in about 1 year in 10. Light frost (36°F) can damage tender plants; a hard freeze (28°F) kills most annuals.
| Temperature | Last spring: 90% / 50% / 10% chance | First fall: 10% / 50% / 90% chance | Growing season (50%) | Years with at least one |
|---|---|---|---|---|
| Light frost (36°F) | May 4 · May 15 · May 28 | Sep 17 · Sep 29 · Oct 11 | 135 days | 100% |
| Frost / freeze (32°F) | Apr 23 · May 3 · May 16 | Sep 27 · Oct 10 · Oct 25 | 158 days | 100% |
| Hard freeze (28°F) | Apr 6 · Apr 20 · May 3 | Oct 7 · Oct 23 · Nov 6 | 184 days | 100% |
Planting calendar for Dover
Planting windows from the University of Maryland Extension calendar, shifted to your average frost dates. Use them as a starting point and adjust for seed packet instructions and local conditions.
| Crop | Task | Window |
|---|---|---|
| Tomatoes | Start seeds indoors | Apr 2 – Jun 8 |
| Tomatoes | Transplant outdoors | May 19 – Jun 20 |
| Peppers | Start seeds indoors | Apr 2 – May 3 |
| Peppers | Transplant outdoors | Jun 2 – Jul 3 |
| Eggplant | Start seeds indoors | Apr 19 – May 18 |
| Eggplant | Transplant outdoors | Jun 2 – Jul 3 |
| Cucumbers | Sow outdoors | Jun 2 – Jun 30 |
| Summer squash | Sow outdoors | May 19 – Jul 3 |
| Winter squash & pumpkins | Sow outdoors | Jun 2 – Jul 3 |
| Snap beans | Sow outdoors | May 19 – Jul 23 |
| Sweet corn | Sow outdoors | May 19 – Jun 20 |
| Watermelon & cantaloupe | Sow outdoors | Jun 2 – Jul 3 |
| Okra | Sow outdoors | May 26 – Jun 18 |
| Peas | Sow outdoors (spring) | Apr 2 – May 18 |
| Potatoes | Plant outdoors (spring) | Apr 2 – Jun 2 |
| Onions | Start seeds indoors (spring) | Feb 19 – Mar 18 |
| Onions | Transplant outdoors (spring) | Apr 19 – May 18 |
| Broccoli | Start seeds indoors (spring) | Mar 15 – Apr 18 |
| Broccoli | Transplant outdoors (spring) | Apr 19 – May 18 |
| Broccoli | Start seeds indoors (fall) | Jun 10 – Jun 20 |
| Broccoli | Transplant outdoors (fall) | Jul 10 – Jul 21 |
| Cabbage | Start seeds indoors (spring) | Mar 5 – Apr 2 |
| Cabbage | Transplant outdoors (spring) | Apr 2 – May 3 |
| Cabbage | Start seeds indoors (fall) | May 31 – Jun 30 |
| Cabbage | Transplant outdoors (fall) | Jun 30 – Jul 31 |
| Leaf lettuce | Sow outdoors (spring) | Apr 2 – Jun 18 |
| Leaf lettuce | Sow outdoors (fall) | Jun 30 – Aug 16 |
| Spinach | Sow outdoors (spring) | Mar 26 – May 9 |
| Spinach | Sow outdoors (fall) | Jul 17 – Aug 21 |
| Radishes | Sow outdoors (spring) | Apr 2 – May 23 |
| Radishes | Sow outdoors (fall) | Jun 30 – Aug 31 |
| Kale | Sow outdoors (spring) | Apr 19 – May 9 |
| Kale | Sow outdoors (fall) | Jun 23 – Jul 31 |
| Carrots | Sow outdoors (spring) | May 3 – Jun 18 |
| Carrots | Sow outdoors (fall) | May 31 – Jul 16 |
| Garlic | Plant outdoors (fall) | Sep 30 – Oct 31 |
Where these dates come from
ZIP code 03822 is matched to the NOAA station Durham 2 N, NH, 5.3 km away, at 119 ft elevation (53 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Durham 2 N, NH (used) | 119 ft | May 3 | Oct 10 |
| Durham, NH | 75 ft | May 8 | Oct 4 |
| Rochester Skyhaven Ap, NH | 323 ft | Apr 30 | Oct 9 |
| Durham 2 Ssw, NH | 63 ft | May 7 | Oct 4 |
Frost dates near Dover
- Dover, NH 03821 · last May 3, first Oct 10
- Rollinsford, NH 03869 · last May 3, first Oct 10
- Somersworth, NH 03878 · last Apr 30, first Oct 9
- Madbury, NH 03823 · last May 3, first Oct 10
- South Berwick, ME 03908 · last May 3, first Oct 10
- Durham, NH 03824 · last May 7, first Oct 4
- Berwick, ME 03901 · last Apr 30, first Oct 9
- Eliot, ME 03903 · last May 7, first Oct 4
Frequently asked questions
- When is the last frost in Dover, NH?
- For ZIP code 03822, the average last spring frost (32°F) is May 3, based on NOAA 1991-2020 climate normals for the Durham 2 N, NH weather station. There is a 1-in-10 chance of a frost after May 16.
- When is the first frost in Dover, NH?
- The average first fall frost (32°F) is October 10. There is a 1-in-10 chance of frost by September 27, so tender plants are at risk from that point on.
- How long is the growing season in 03822?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 158 days long.
- Are these frost dates a forecast?
- No. They are 30-year averages and probabilities from NOAA weather station records. Use them to plan, then watch your local forecast before planting tender crops or leaving them uncovered.