| 2023 Hardiness Zone: | Zone 6b: -5°F to 0°F Zone 7b: 5°F to 10°F Zone 7a: 0°F to 5°F |
| 2012 Hardiness Zone: | Zone 6a: -10°F to -5°F Zone 6b: -5°F to 0°F Zone 7b: 5°F to 10°F Zone 7a: 0°F to 5°F |
| 1990 Hardiness Zone: | Zone 6b: -5F to 0F |
| Average First Frost Date: | Sep. 21 - Sep. 30 |
| Average Last Frost Date: | Jun. 1 - Jun. 10 |
| Koppen-Geiger Climate Zone: | BSk - Cold Semi-Arid Climate |
| Ecoregion: | 10f - Dissected Loess Uplands |
| Heat Zone Days: | 31 - 45 days Over 86°F |
Annual Climate Data for ZIP Code 99403 - Clarkston, WA | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 28 | 31 | 35 | 40 | 46 | 53 | 58 | 58 | 50 | 41 | 34 | 28 | 42 |
| Avg Max Temp (°F) | 39 | 45 | 53 | 61 | 69 | 77 | 87 | 87 | 76 | 62 | 46 | 39 | 62 |
| Avg Precip (In.) | 1.13 | .84 | 1.16 | 1.17 | 1.4 | 1.05 | .64 | .71 | .7 | .84 | 1.16 | .88 | 11.68 |