Richland, Washington has a Cold Desert Climate climate (Köppen classification: BWk). Average annual temperatures range from 5.6 °C (low) to 18.8 °C (high). Annual precipitation averages 200.9 Millimeters. 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 | -2 °C | 5.2 °C | 28.19 mm |
| February | -1.6 °C | 8.8 °C | 20.07 mm |
| March | 1.3 °C | 14.3 °C | 16 mm |
| April | 4.4 °C | 18.9 °C | 16.26 mm |
| May | 8.6 °C | 24 °C | 18.8 mm |
| June | 12.1 °C | 27.7 °C | 15.75 mm |
| July | 15.2 °C | 32.9 °C | 4.32 mm |
| August | 14.8 °C | 32.3 °C | 6.35 mm |
| September | 10.3 °C | 26.9 °C | 5.59 mm |
| October | 4.9 °C | 18.7 °C | 16.26 mm |
| November | 0.7 °C | 10.4 °C | 23.62 mm |
| December | -2.1 °C | 4.9 °C | 29.72 mm |
| Annual | 5.6 °C | 18.8 °C | 200.93 mm |
| 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 : -15°C to -12.2°C |
| Plant Hardiness Zone - 2012 | Zone 7b : -15°C to -12.2°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | BWk - Cold Desert Climate |