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Frost dates for Flagstaff, Arizona

In a typical year, Flagstaff’s last spring frost lands around Jun 4 and the first fall frost around Sep 28, a growing season of about 116 days. These are odds drawn from 30-year NOAA climate normals, not a promise. USDA zone 6a.

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

Last spring frost and first fall frost odds for Flagstaff, Arizona
OddsLast spring frostFirst fall frost
10 percentMay 21Sep 16
50 percentJun 4Sep 28
90 percentJun 19Oct 9

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 Flagstaff is typically around 46°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 Flagstaff, Arizona?

Flagstaff’s last spring frost falls around June 4 in a typical year. One year in ten it is done by May 21, and one year in ten frost holds on until June 19. Frost-sensitive planting usually waits for the late side of that band.

When is the first fall frost in Flagstaff?

The first fall frost arrives around September 28 in a typical year, as early as September 16 in an early year and as late as October 9 in a late one.

How long is the growing season in Flagstaff?

About 116 days, counted between the typical last spring frost and the typical first fall frost.

What USDA zone is Flagstaff in?

Flagstaff is in USDA hardiness zone 6a 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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