Skip to content

Frost dates for Missoula, Montana

In a typical year, Missoula’s last spring frost lands around May 10 and the first fall frost around Oct 1, a growing season of about 144 days. These are odds drawn from 30-year NOAA climate normals, not a promise. USDA zone 5b.

Right now the typical frost season has arrived; planting waits for spring.

Last spring frost and first fall frost odds for Missoula, Montana
OddsLast spring frostFirst fall frost
10 percentApr 27Sep 16
50 percentMay 10Oct 1
90 percentMay 28Oct 15

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 Missoula is typically around 44°F at 4 inches this time of year, estimated from the last two weeks of normal air temperatures.

See what is plantable in your ZIP with the what-to-plant lookup.

Common questions

When is the last frost in Missoula, Montana?

Missoula’s last spring frost falls around May 10 in a typical year. One year in ten it is done by April 27, and one year in ten frost holds on until May 28. Frost-sensitive planting usually waits for the late side of that band.

When is the first fall frost in Missoula?

The first fall frost arrives around October 1 in a typical year, as early as September 16 in an early year and as late as October 15 in a late one.

How long is the growing season in Missoula?

About 144 days, counted between the typical last spring frost and the typical first fall frost.

What USDA zone is Missoula in?

Missoula is in USDA hardiness zone 5b 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

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.

Set up your garden