Frost dates for 04364Winthrop, ME
The average last spring frost in Winthrop is April 27 and the average first fall frost is October 16, giving a typical growing season of about 172 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 27
- Average first fall frost
- Oct 16
- Growing season
- 172 days
Safer after May 7 (1-in-10 risk)
Possible by Oct 2 (1-in-10 risk)
Last frost typically in 177 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) | Apr 28 · May 8 · May 20 | Sep 24 · Oct 4 · Oct 17 | 149 days | 100% |
| Frost / freeze (32°F) | Apr 15 · Apr 27 · May 7 | Oct 2 · Oct 16 · Oct 31 | 172 days | 100% |
| Hard freeze (28°F) | Apr 3 · Apr 15 · Apr 26 | Oct 14 · Oct 31 · Nov 12 | 197 days | 100% |
Planting calendar for Winthrop
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 | Mar 27 – Jun 2 |
| Tomatoes | Transplant outdoors | May 13 – Jun 26 |
| Peppers | Start seeds indoors | Mar 27 – Apr 27 |
| Peppers | Transplant outdoors | May 27 – Jun 27 |
| Eggplant | Start seeds indoors | Apr 13 – May 12 |
| Eggplant | Transplant outdoors | May 27 – Jun 27 |
| Cucumbers | Sow outdoors | May 27 – Jul 6 |
| Summer squash | Sow outdoors | May 13 – Jun 27 |
| Winter squash & pumpkins | Sow outdoors | May 27 – Jun 27 |
| Snap beans | Sow outdoors | May 13 – Jul 29 |
| Sweet corn | Sow outdoors | May 13 – Jun 26 |
| Watermelon & cantaloupe | Sow outdoors | May 27 – Jun 27 |
| Okra | Sow outdoors | May 20 – Jun 12 |
| Peas | Sow outdoors (spring) | Mar 27 – May 12 |
| Potatoes | Plant outdoors (spring) | Mar 27 – May 27 |
| Onions | Start seeds indoors (spring) | Feb 13 – Mar 12 |
| Onions | Transplant outdoors (spring) | Apr 13 – May 12 |
| Broccoli | Start seeds indoors (spring) | Mar 9 – Apr 12 |
| Broccoli | Transplant outdoors (spring) | Apr 13 – May 12 |
| Broccoli | Start seeds indoors (fall) | Jun 16 – Jun 26 |
| Broccoli | Transplant outdoors (fall) | Jul 16 – Jul 27 |
| Cabbage | Start seeds indoors (spring) | Feb 27 – Mar 27 |
| Cabbage | Transplant outdoors (spring) | Mar 27 – Apr 27 |
| Cabbage | Start seeds indoors (fall) | Jun 6 – Jul 6 |
| Cabbage | Transplant outdoors (fall) | Jul 6 – Aug 6 |
| Leaf lettuce | Sow outdoors (spring) | Mar 27 – Jun 12 |
| Leaf lettuce | Sow outdoors (fall) | Jul 6 – Aug 22 |
| Spinach | Sow outdoors (spring) | Mar 20 – May 3 |
| Spinach | Sow outdoors (fall) | Jul 23 – Aug 27 |
| Radishes | Sow outdoors (spring) | Mar 27 – May 17 |
| Radishes | Sow outdoors (fall) | Jul 6 – Sep 6 |
| Kale | Sow outdoors (spring) | Apr 13 – May 3 |
| Kale | Sow outdoors (fall) | Jun 29 – Aug 6 |
| Carrots | Sow outdoors (spring) | Apr 27 – Jun 12 |
| Carrots | Sow outdoors (fall) | Jun 6 – Jul 22 |
| Garlic | Plant outdoors (fall) | Oct 6 – Nov 6 |
Where these dates come from
ZIP code 04364 is matched to the NOAA station Augusta State Ap, ME, 12.8 km away, at 350 ft elevation (140 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Augusta State Ap, ME (used) | 350 ft | Apr 27 | Oct 16 |
| Gardiner, ME | 133 ft | May 1 | Oct 11 |
| Livermore Falls 1 E, ME | 380 ft | May 11 | Sep 29 |
| Turner, ME | 565 ft | May 1 | Oct 10 |
Frost dates near Winthrop
- East Winthrop, ME 04343 · last Apr 27, first Oct 16
- Manchester, ME 04351 · last Apr 27, first Oct 16
- North Monmouth, ME 04265 · last Apr 27, first Oct 16
- Readfield, ME 04355 · last Apr 27, first Oct 16
- Wayne, ME 04284 · last Apr 27, first Oct 16
- Augusta, ME 04336 · last Apr 27, first Oct 16
- Monmouth, ME 04259 · last May 1, first Oct 11
- Hallowell, ME 04347 · last Apr 27, first Oct 16
Frequently asked questions
- When is the last frost in Winthrop, ME?
- For ZIP code 04364, the average last spring frost (32°F) is April 27, based on NOAA 1991-2020 climate normals for the Augusta State Ap, ME weather station. There is a 1-in-10 chance of a frost after May 7.
- When is the first frost in Winthrop, ME?
- The average first fall frost (32°F) is October 16. There is a 1-in-10 chance of frost by October 2, so tender plants are at risk from that point on.
- How long is the growing season in 04364?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 172 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.