Westbrook, ME 04029 Frost Dates
04029, near Westbrook, ME: the frost window
The last spring frost here typically falls around 04/30, about 245 days from today. Fall's first freeze usually shows up around 10/20, roughly 172 days after the last spring frost.
Zone 5a (-20 to -15°F average annual minimum) comes from the USDA Plant Hardiness Zone Map; the frost dates above are the 1991-2020 normal at the nearest reporting NOAA station for Westbrook, not a forecast for this year.
Stretching the season past the first frost
Westbrook's growing season runs out in roughly 8 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
Why 04/30 isn't a guarantee
04/30 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/18 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/12 and only about 1 year in 10 sees frost after that.
Westbrook against the rest of the dataset
Westbrook's growing season runs about 172 days, ranking 28,187 of 40,283 US ZIP codes measured here, longest to shortest. Within ME, it ranks 81 of 456.
Learn more
Two guides worth reading on 04029: the frost range, on how to read the range around Westbrook's dates instead of trusting one, and local microclimates, on what one yard in Westbrook can differ from the 04029 normal.