When to plant in Westbrook, ME
USDA Zone 5bWestbrook, Maine frost dates, USDA zone, and a full-year planting calendar, drawn from the nearest NOAA station and tuned to the local season.
Zone 5b means Westbrook sees real winter cold, but a good range of perennials survive; the frost dates above govern when annual vegetables go out.
The average last spring frost in Westbrook is now 5 days earlier than in the 1981–2010 normals. See how frost dates are shifting nationwide →
Frost probability
PORTLAND INTL JETPORT · 1991–2020The date the last spring and first fall frost occur, by threshold and probability. A 90% date is later in spring — and earlier in fall — than a 10% date; the 50% · 32°F row is what most gardeners plan around. These are Westbrook’s own odds, recorded at PORTLAND INTL JETPORT.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | May 20 | May 7 | Apr 28 | Sep 24 | Oct 4 | Oct 17 |
| 32°F | May 7 | Apr 26 | Apr 16 | Oct 2 | Oct 15 | Oct 30 |
| 28°F | Apr 25 | Apr 14 | Apr 3 | Oct 14 | Oct 27 | Nov 9 |
Download this table as CSV ↓ — every threshold and probability, plus this city’s planting-window dates.
What to plant now
TODAY · JULY 19Full-year planting calendar
Each bar is the exact window to take a planting action in Westbrook, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 21 km · complete 32°F normalsWhen stations disagree by more than a few days, that spread is real microclimate variation — elevation, water, urban heat. Judge which station best matches your own yard.
Westbrook planting FAQ
When is the last spring frost in Westbrook, ME?
On average, the last spring frost in Westbrook is around April 26 (50% probability at 32°F, from 1991–2020 NOAA normals). Wait until after this date to set out tender plants like tomatoes and peppers.
When is the first fall frost in Westbrook, ME?
In Westbrook, the first 32°F freeze of fall lands around October 15 on average. Time your last harvests and any season-extension cover before it.
What hardiness zone is Westbrook in?
Westbrook is in USDA hardiness zone 5b. In zone 5b, winters are cold — pick cold-hardy varieties and protect tender crops.
How long is the growing season in Westbrook?
There are roughly 172 frost-free days in Westbrook (a moderate growing season), running from the average last frost around April 26 to the first fall frost near October 15.
When should I plant tomatoes in Westbrook?
In Westbrook, start tomato seeds indoors around March 1–March 15, then transplant seedlings outdoors around May 3 once the danger of frost has passed.
Never miss a window in Westbrook
An email when it’s time to start seeds, transplant, and sow — timed to Westbrook’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reachFrost dates recorded at PORTLAND INTL JETPORT, 8 km from the city center · 1991–2020 NOAA climate normals · zone from the USDA/PRISM 2023 map. How we compute this.
BlissGarden. "When to Plant in Westbrook, ME — Frost Dates & Zone 5b." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USW00014764. Retrieved from https://blissgarden.com/maine/westbrook.