Frost dates for South Portland, Maine
In a typical year, South Portland’s last spring frost lands around Apr 26 and the first fall frost around Oct 15, a growing season of about 172 days. These are odds drawn from 30-year NOAA climate normals, not a promise. USDA zone 6a.
Right now the typical frost season has arrived; planting waits for spring.
| Odds | Last spring frost | First fall frost |
|---|---|---|
| 10 percent | Apr 16 | Oct 2 |
| 50 percent | Apr 26 | Oct 15 |
| 90 percent | May 7 | Oct 30 |
A 10 percent year is an early year, a 90 percent year a late one. Frost-sensitive planting usually waits for the 90 percent side of the last-frost band.
Soil in South Portland is typically around 49°F at 4 inches this time of year, estimated from the last two weeks of normal air temperatures.
Plantable now in South Portland
- Garlic (Music)
Timing comes from the same temperature engine the app uses, run against South Portland’s normals for today.
Common questions
When is the last frost in South Portland, Maine?
South Portland’s last spring frost falls around April 26 in a typical year. One year in ten it is done by April 16, and one year in ten frost holds on until May 7. Frost-sensitive planting usually waits for the late side of that band.
When is the first fall frost in South Portland?
The first fall frost arrives around October 15 in a typical year, as early as October 2 in an early year and as late as October 30 in a late one.
How long is the growing season in South Portland?
About 172 days, counted between the typical last spring frost and the typical first fall frost.
What USDA zone is South Portland in?
South Portland is in USDA hardiness zone 6a under the 2023 USDA Plant Hardiness Zone Map.
Dates come from 30-year NOAA climate normals for the nearest reporting station. They describe odds, not a forecast.
Nearby cities
- Portland, ME (around Apr 26 to Oct 15)
- Lewiston, ME (around May 1 to Oct 10)
- Dover, NH (around May 3 to Oct 10)
- Concord, NH (around May 14 to Sep 29)
- Manchester, NH (around Apr 30 to Oct 11)
Row & Bed is a plant reference built around your garden: your zone, your frost dates, your forecast, and a cited page for every variety in your beds.
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