| 2023 Hardiness Zone: | Zone 7a: 0°F to 5°F |
| 2012 Hardiness Zone: | Zone 6b: -5°F to 0°F Zone 7a: 0°F to 5°F |
| 1990 Hardiness Zone: | Zone 6a: -10F to -5F |
| Average First Frost Date: | Oct. 11 - Oct. 20 |
| Average Last Frost Date: | May 1 - May 10 |
| Koppen-Geiger Climate Zone: | BSk - Cold Semi-Arid Climate |
| Ecoregion: | 12a - Treasure Valley |
| Heat Zone Days: | 46 - 60 days Over 86°F |
Annual Climate Data for ZIP Code 83605 - Caldwell, ID | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 22 | 27 | 33 | 38 | 46 | 53 | 58 | 56 | 46 | 37 | 29 | 22 | 39 |
| Avg Max Temp (°F) | 37 | 46 | 57 | 66 | 74 | 83 | 91 | 91 | 80 | 67 | 49 | 38 | 65 |
| Avg Precip (In.) | 1.43 | 1.06 | 1.25 | 1.06 | 1.03 | .69 | .3 | .33 | .56 | .71 | 1.24 | 1.33 | 10.99 |