| 2023 Hardiness Zone: | Zone 7b: 5°F to 10°F |
| 2012 Hardiness Zone: | 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 7a: 0F 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: | 10g - Yakima Folds |
| Heat Zone Days: | 46 - 60 days Over 86°F |
Annual Climate Data for ZIP Code 99338 - Kennewick, WA | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 26 | 31 | 34 | 39 | 46 | 53 | 59 | 59 | 51 | 42 | 34 | 28 | 42 |
| Avg Max Temp (°F) | 38 | 46 | 54 | 62 | 72 | 80 | 88 | 87 | 77 | 62 | 47 | 39 | 63 |
| Avg Precip (In.) | 1.34 | .79 | .79 | .67 | .84 | .77 | .26 | .31 | .37 | .84 | 1.4 | 1.42 | 9.79 |