Portland, TN 37148 Frost Dates
Portland, TN: when does the frost end?
Typically, the last spring freeze lands around 04/05, roughly 220 days out. Fall's first freeze usually shows up around 11/01, roughly 210 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Portland in Zone 7b (5 to 10°F average annual minimum); frost dates are NOAA's 1991-2020 station normal, not this year's forecast.
Stretching the season past the first frost
With roughly 9 weeks until Portland's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
Why 04/05 isn't a guarantee
04/05 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 03/21 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 04/19 and only about 1 year in 10 sees frost after that.
Portland against the rest of the dataset
About 210 days separate Portland's last and first frost, putting it 14,982 of 40,283 ZIP codes nationally. Within TN, it ranks 326 of 770.
Learn more
Before leaning on 37148's figures: local microclimates explains what one yard in Portland can differ from the 37148 normal, while zone vs. frost date explains why Zone 7b and Portland's frost date answer different questions.