Richland, Washington has a Cold Desert Climate climate (Köppen classification: BWk). Average annual temperatures range from 42 °F (low) to 65.8 °F (high). Annual precipitation averages 7.9 Inches. Richland is located in USDA Plant Hardiness Zone 7b. The growing season typically runs from the last frost around Mar. 21 - Mar. 31 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 28.4 °F | 41.4 °F | 1.11 in. |
| February | 29.2 °F | 47.9 °F | 0.79 in. |
| March | 34.4 °F | 57.8 °F | 0.63 in. |
| April | 39.9 °F | 66.0 °F | 0.64 in. |
| May | 47.4 °F | 75.2 °F | 0.74 in. |
| June | 53.8 °F | 81.9 °F | 0.62 in. |
| July | 59.4 °F | 91.2 °F | 0.17 in. |
| August | 58.7 °F | 90.2 °F | 0.25 in. |
| September | 50.6 °F | 80.5 °F | 0.22 in. |
| October | 40.9 °F | 65.7 °F | 0.64 in. |
| November | 33.3 °F | 50.7 °F | 0.93 in. |
| December | 28.2 °F | 40.8 °F | 1.17 in. |
| Annual | 42 °F | 65.8 °F | 7.91 in. |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Mar. 21 - Mar. 31 |
| Average Days With Frost | 75-100 Days |
| Plant Hardiness Zone | Zone 7b : 5°F to 10°F |
| Plant Hardiness Zone - 2012 | Zone 7b : 5°F to 10°F |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | BWk - Cold Desert Climate |