Rapid City, SD Frost Dates
The last spring frost in Rapid City usually comes around May 12 and the first fall frost around October 1.
| Spring (last) | Fall (first) | |
|---|---|---|
| Frost, 32°F | May 12 | October 1 |
| Hard freeze, 28°F | May 2 | October 9 |
Growing season: about 139 days.
Frequently asked questions
When is the last frost in Rapid City, SD?
The median date of the last spring frost (32°F) is May 12. In half of years the last frost comes earlier and in half it comes later, so waiting a week or two past May 12 lowers the risk for tender plants.
When is the first frost in Rapid City?
The median date of the first fall frost (32°F) is October 1, and a hard freeze (28°F) usually follows around October 9.
How long is the growing season in Rapid City?
About 139 days between the median last spring frost and first fall frost.
NOAA NCEI U.S. Climate Normals 1991-2020, station USW00024090. Median (50% probability) dates. Low spots and valleys can frost later in spring and earlier in fall than the station.