South Portland, ME 04101 Frost Dates
Frost dates for South Portland, ME, ZIP 04101
Around 04/26 is the usual last spring frost, about 241 days away. The first fall frost typically arrives around 10/15, about 170 frost-free days later.
Zone 6a (-10 to -5°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 South Portland, not a forecast for this year.
What to do before the first frost
Zone 6a around South Portland has about 7 weeks left before the first fall frost — that's the usual window to get a cold frame up if you want to keep harvesting past it.
How much risk comes with planting early here
04/26 is the middle of 30 years of NOAA records, not a promise. Plant by 04/16 and you're betting against frost in roughly 9 years out of 10. 05/07 is the safer bet, historically only a 1-in-10 chance of frost that late.
How South Portland compares
About 170 days separate South Portland's last and first frost, putting it 28,910 of 40,283 ZIP codes nationally. Within ME, it ranks 124 of 456.
Learn more
the frost range explains how to read the range around South Portland's dates instead of trusting one, and local microclimates explains what one yard in South Portland can differ from the 04101 normal.