Frost dates for 04539Bristol, ME
The average last spring frost in Bristol is May 8 and the average first fall frost is October 7, giving a typical growing season of about 151 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 8
- Average first fall frost
- Oct 7
- Growing season
- 151 days
Safer after May 20 (1-in-10 risk)
Possible by Sep 24 (1-in-10 risk)
Last frost typically in 188 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 8 · May 20 · Jun 1 | Sep 13 · Sep 27 · Oct 8 | 129 days | 100% |
| Frost / freeze (32°F) | Apr 26 · May 8 · May 20 | Sep 24 · Oct 7 · Oct 21 | 151 days | 100% |
| Hard freeze (28°F) | Apr 12 · Apr 26 · May 6 | Oct 5 · Oct 21 · Nov 4 | 177 days | 100% |
Planting calendar for Bristol
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 7 – Jun 13 |
| Tomatoes | Transplant outdoors | May 24 – Jun 17 |
| Peppers | Start seeds indoors | Apr 7 – May 8 |
| Peppers | Transplant outdoors | Jun 7 – Jul 8 |
| Eggplant | Start seeds indoors | Apr 24 – May 23 |
| Eggplant | Transplant outdoors | Jun 7 – Jul 8 |
| Cucumbers | Sow outdoors | Jun 7 – Jun 27 |
| Summer squash | Sow outdoors | May 24 – Jul 8 |
| Winter squash & pumpkins | Sow outdoors | Jun 7 – Jul 8 |
| Snap beans | Sow outdoors | May 24 – Jul 20 |
| Sweet corn | Sow outdoors | May 24 – Jun 17 |
| Watermelon & cantaloupe | Sow outdoors | Jun 7 – Jul 8 |
| Okra | Sow outdoors | May 31 – Jun 23 |
| Peas | Sow outdoors (spring) | Apr 7 – May 23 |
| Potatoes | Plant outdoors (spring) | Apr 7 – Jun 7 |
| Onions | Start seeds indoors (spring) | Feb 24 – Mar 23 |
| Onions | Transplant outdoors (spring) | Apr 24 – May 23 |
| Broccoli | Start seeds indoors (spring) | Mar 20 – Apr 23 |
| Broccoli | Transplant outdoors (spring) | Apr 24 – May 23 |
| Broccoli | Start seeds indoors (fall) | Jun 7 – Jun 17 |
| Broccoli | Transplant outdoors (fall) | Jul 7 – Jul 18 |
| Cabbage | Start seeds indoors (spring) | Mar 10 – Apr 7 |
| Cabbage | Transplant outdoors (spring) | Apr 7 – May 8 |
| Cabbage | Start seeds indoors (fall) | May 28 – Jun 27 |
| Cabbage | Transplant outdoors (fall) | Jun 27 – Jul 28 |
| Leaf lettuce | Sow outdoors (spring) | Apr 7 – Jun 23 |
| Leaf lettuce | Sow outdoors (fall) | Jun 27 – Aug 13 |
| Spinach | Sow outdoors (spring) | Mar 31 – May 14 |
| Spinach | Sow outdoors (fall) | Jul 14 – Aug 18 |
| Radishes | Sow outdoors (spring) | Apr 7 – May 28 |
| Radishes | Sow outdoors (fall) | Jun 27 – Aug 28 |
| Kale | Sow outdoors (spring) | Apr 24 – May 14 |
| Kale | Sow outdoors (fall) | Jun 20 – Jul 28 |
| Carrots | Sow outdoors (spring) | May 8 – Jun 23 |
| Carrots | Sow outdoors (fall) | May 28 – Jul 13 |
| Garlic | Plant outdoors (fall) | Sep 27 – Oct 28 |
Where these dates come from
ZIP code 04539 is matched to the NOAA station Wiscasset Ap, ME, 17.4 km away, at 68 ft elevation (25 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Wiscasset Ap, ME (used) | 68 ft | May 8 | Oct 7 |
| Newcastle, ME | 213 ft | Apr 27 | Oct 18 |
| Westport Island, ME | 90 ft | Apr 28 | Oct 21 |
| Tenants Harbor, ME | 21 ft | Apr 27 | Oct 25 |
Frost dates near Bristol
- Round Pond, ME 04564 · last May 8, first Oct 7
- Walpole, ME 04573 · last May 8, first Oct 7
- Pemaquid, ME 04558 · last Apr 27, first Oct 18
- Chamberlain, ME 04541 · last May 8, first Oct 7
- Bremen, ME 04551 · last Apr 27, first Oct 18
- Isle Of Springs, ME 04549 · last Apr 27, first Oct 18
- Squirrel Island, ME 04570 · last Apr 27, first Oct 18
- Damariscotta, ME 04543 · last Apr 27, first Oct 18
Frequently asked questions
- When is the last frost in Bristol, ME?
- For ZIP code 04539, the average last spring frost (32°F) is May 8, based on NOAA 1991-2020 climate normals for the Wiscasset Ap, ME weather station. There is a 1-in-10 chance of a frost after May 20.
- When is the first frost in Bristol, ME?
- The average first fall frost (32°F) is October 7. There is a 1-in-10 chance of frost by September 24, so tender plants are at risk from that point on.
- How long is the growing season in 04539?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 151 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.