| 2023 Hardiness Zone: | Zone 7b: 5°F to 10°F |
| 2012 Hardiness Zone: | 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. 21 - Oct. 31 |
| Average Last Frost Date: | Apr. 11 - Apr. 20 |
| Koppen-Geiger Climate Zone: | BWk - Cold Desert Climate |
| Ecoregion: | 10e - Pleistocene Lake Basins |
| Heat Zone Days: | 46 - 60 days Over 86°F |
Annual Climate Data for ZIP Code 99352 - Richland, WA | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 26 | 29 | 35 | 40 | 47 | 54 | 58 | 58 | 50 | 40 | 33 | 27 | 42 |
| Avg Max Temp (°F) | 40 | 47 | 57 | 65 | 73 | 81 | 88 | 88 | 79 | 65 | 49 | 40 | 64 |
| Avg Precip (In.) | 1 | .77 | .73 | .57 | .62 | .42 | .25 | .31 | .35 | .55 | 1.1 | 1.09 | 7.76 |