Frost dates for 04092Westbrook, ME
The average last spring frost in Westbrook is April 26 and the average first fall frost is October 15, giving a typical growing season of about 170 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 26
- Average first fall frost
- Oct 15
- Growing season
- 170 days
Safer after May 7 (1-in-10 risk)
Possible by Oct 2 (1-in-10 risk)
Last frost typically in 176 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 7 · May 20 | Sep 24 · Oct 4 · Oct 17 | 149 days | 100% |
| Frost / freeze (32°F) | Apr 16 · Apr 26 · May 7 | Oct 2 · Oct 15 · Oct 30 | 170 days | 100% |
| Hard freeze (28°F) | Apr 3 · Apr 14 · Apr 25 | Oct 14 · Oct 27 · Nov 9 | 195 days | 100% |
Planting calendar for Westbrook
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 26 – Jun 1 |
| Tomatoes | Transplant outdoors | May 12 – Jun 25 |
| Peppers | Start seeds indoors | Mar 26 – Apr 26 |
| Peppers | Transplant outdoors | May 26 – Jun 26 |
| Eggplant | Start seeds indoors | Apr 12 – May 11 |
| Eggplant | Transplant outdoors | May 26 – Jun 26 |
| Cucumbers | Sow outdoors | May 26 – Jul 5 |
| Summer squash | Sow outdoors | May 12 – Jun 26 |
| Winter squash & pumpkins | Sow outdoors | May 26 – Jun 26 |
| Snap beans | Sow outdoors | May 12 – Jul 28 |
| Sweet corn | Sow outdoors | May 12 – Jun 25 |
| Watermelon & cantaloupe | Sow outdoors | May 26 – Jun 26 |
| Okra | Sow outdoors | May 19 – Jun 11 |
| Peas | Sow outdoors (spring) | Mar 26 – May 11 |
| Potatoes | Plant outdoors (spring) | Mar 26 – May 26 |
| Onions | Start seeds indoors (spring) | Feb 12 – Mar 11 |
| Onions | Transplant outdoors (spring) | Apr 12 – May 11 |
| Broccoli | Start seeds indoors (spring) | Mar 8 – Apr 11 |
| Broccoli | Transplant outdoors (spring) | Apr 12 – May 11 |
| Broccoli | Start seeds indoors (fall) | Jun 15 – Jun 25 |
| Broccoli | Transplant outdoors (fall) | Jul 15 – Jul 26 |
| Cabbage | Start seeds indoors (spring) | Feb 26 – Mar 26 |
| Cabbage | Transplant outdoors (spring) | Mar 26 – Apr 26 |
| Cabbage | Start seeds indoors (fall) | Jun 5 – Jul 5 |
| Cabbage | Transplant outdoors (fall) | Jul 5 – Aug 5 |
| Leaf lettuce | Sow outdoors (spring) | Mar 26 – Jun 11 |
| Leaf lettuce | Sow outdoors (fall) | Jul 5 – Aug 21 |
| Spinach | Sow outdoors (spring) | Mar 19 – May 2 |
| Spinach | Sow outdoors (fall) | Jul 22 – Aug 26 |
| Radishes | Sow outdoors (spring) | Mar 26 – May 16 |
| Radishes | Sow outdoors (fall) | Jul 5 – Sep 5 |
| Kale | Sow outdoors (spring) | Apr 12 – May 2 |
| Kale | Sow outdoors (fall) | Jun 28 – Aug 5 |
| Carrots | Sow outdoors (spring) | Apr 26 – Jun 11 |
| Carrots | Sow outdoors (fall) | Jun 5 – Jul 21 |
| Garlic | Plant outdoors (fall) | Oct 5 – Nov 5 |
Where these dates come from
ZIP code 04092 is matched to the NOAA station Portland Intl Jetport, ME, 6 km away, at 45 ft elevation (31 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Portland Intl Jetport, ME (used) | 45 ft | Apr 26 | Oct 15 |
| West Buxton 2 Nnw, ME | 220 ft | May 7 | Oct 4 |
| Windham 2Nw, ME | 443 ft | Apr 30 | Oct 20 |
| Gray, ME | 378 ft | Apr 28 | Oct 19 |
Frost dates near Westbrook
- Westbrook, ME 04098 · last Apr 26, first Oct 15
- Portland, ME 04103 · last Apr 26, first Oct 15
- South Windham, ME 04082 · last Apr 26, first Oct 15
- Gorham, ME 04038 · last May 7, first Oct 4
- South Portland, ME 04106 · last Apr 26, first Oct 15
- Falmouth, ME 04105 · last Apr 26, first Oct 15
- Scarborough, ME 04074 · last Apr 26, first Oct 15
- Windham, ME 04062 · last May 7, first Oct 4
Frequently asked questions
- When is the last frost in Westbrook, ME?
- For ZIP code 04092, the average last spring frost (32°F) is April 26, based on NOAA 1991-2020 climate normals for the Portland Intl Jetport, ME weather station. There is a 1-in-10 chance of a frost after May 7.
- When is the first frost in Westbrook, ME?
- The average first fall frost (32°F) is October 15. 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 04092?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 170 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.