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Frost dates for Lewiston, Idaho

In a typical year, Lewiston’s last spring frost lands around Apr 6 and the first fall frost around Oct 26, a growing season of about 203 days. These are odds drawn from 30-year NOAA climate normals, not a promise. USDA zone 7b.

Right now the growing season is open, with about 1 day until the typical first fall frost.

Last spring frost and first fall frost odds for Lewiston, Idaho
OddsLast spring frostFirst fall frost
10 percentMar 20Oct 10
50 percentApr 6Oct 26
90 percentApr 26Nov 12

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 Lewiston is typically around 51°F at 4 inches this time of year, estimated from the last two weeks of normal air temperatures.

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Common questions

When is the last frost in Lewiston, Idaho?

Lewiston’s last spring frost falls around April 6 in a typical year. One year in ten it is done by March 20, and one year in ten frost holds on until April 26. Frost-sensitive planting usually waits for the late side of that band.

When is the first fall frost in Lewiston?

The first fall frost arrives around October 26 in a typical year, as early as October 10 in an early year and as late as November 12 in a late one.

How long is the growing season in Lewiston?

About 203 days, counted between the typical last spring frost and the typical first fall frost.

What USDA zone is Lewiston in?

Lewiston is in USDA hardiness zone 7b 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

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