Lewiston, ID 83501 Frost Dates
Lewiston, ID: when does the frost end?
Typically, the last spring freeze lands around 04/06, roughly 221 days out. Fall's first freeze usually shows up around 10/26, roughly 200 days after the last spring frost.
Zone 7b (5 to 10°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 Lewiston, not a forecast for this year.
Stretching the season past the first frost
With roughly 8 weeks until Lewiston's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
How much risk comes with planting early here
04/06 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 03/20 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 04/26 and only about 1 year in 10 sees frost after that.
Lewiston against the rest of the dataset
About 200 days separate Lewiston's last and first frost, putting it 17,716 of 40,283 ZIP codes nationally. Within ID, it ranks 1 of 320.
Learn more
Before leaning on 83501's figures: local microclimates explains what one yard in Lewiston can differ from the 83501 normal, while zone vs. frost date explains why Zone 7b and Lewiston's frost date answer different questions.