Last frost date in Nampa, Idaho
April 29
Average last frost in spring. In an early year (1 in 10) it's over by April 15; in a late year (1 in 10) it comes after May 18.
October 13
Average first frost in fall. 1 year in 10 it comes by September 29.
Source: NOAA U.S. Climate Normals 1991–2020, station Nampa Sugar Factory (USC00106305), 1.4 miles from Nampa, elevation 2,470 ft. NOAA National Centers for Environmental Information. These are long-term averages, not a forecast.
This station is also the nearest one for Caldwell, Middleton and Star, so their frost dates are the same as Nampa's.
| Early year | Average | Late year | |
|---|---|---|---|
| Last frost in spring | Apr 15 | Apr 29 | May 18 |
| First frost in fall | Sept 29 | Oct 13 | Oct 28 |
Frost-free days in an average year: 164
| Chance in a year | Average last in spring | Average first in fall | |
|---|---|---|---|
| Light frost (36°F) | Every year | May 16 | Sept 30 |
| Frost (32°F) | Every year | Apr 29 | Oct 13 |
| Hard freeze (28°F) | Every year | Apr 11 | Oct 25 |
Nights at 32°F or colder in an average year: 132
What to plant now in Nampa
- Spring planting calendar for an average last frost around April 30 Nampa: April 29
- Fall planting calendar for an average first frost around October 10 Nampa: October 13
Planting dates: USDA Home and Garden Bulletin No. 9 (1967), “Suburban and Farm Vegetable Gardens,” tables 4 and 5. How we match the table.
Nearby in Idaho
- Garden City 15 mi · last frost May 17
- Eagle 15 mi · last frost Apr 30
- Boise City 17 mi · last frost Apr 24
- Mountain Home 54 mi · last frost May 2
- Jerome 119 mi · last frost May 2
Updated