Boise, ID Frost Dates
The last spring frost in Boise usually comes around April 24 and the first fall frost around October 21.
| Spring (last) | Fall (first) | |
|---|---|---|
| Frost, 32°F | April 24 | October 21 |
| Hard freeze, 28°F | April 2 | October 31 |
Growing season: about 179 days.
Frequently asked questions
When is the last frost in Boise, ID?
The median date of the last spring frost (32°F) is April 24. In half of years the last frost comes earlier and in half it comes later, so waiting a week or two past April 24 lowers the risk for tender plants.
When is the first frost in Boise?
The median date of the first fall frost (32°F) is October 21, and a hard freeze (28°F) usually follows around October 31.
How long is the growing season in Boise?
About 179 days between the median last spring frost and first fall frost.
NOAA NCEI U.S. Climate Normals 1991-2020, station USW00024131. Median (50% probability) dates. Low spots and valleys can frost later in spring and earlier in fall than the station.