Kennewick, Washington has a Cold Desert Climate climate (Köppen classification: BWk). Average annual temperatures range from 5.8 °C (low) to 18.7 °C (high). Annual precipitation averages 212.9 Millimeters. Kennewick is located in USDA Plant Hardiness Zone 7b. The growing season typically runs from the last frost around Apr. 1 - Apr. 10 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -1.7 °C | 5.3 °C | 30.99 mm |
| February | -1.2 °C | 8.8 °C | 21.34 mm |
| March | 1.6 °C | 14.3 °C | 17.02 mm |
| April | 4.7 °C | 18.8 °C | 17.27 mm |
| May | 8.8 °C | 23.9 °C | 22.61 mm |
| June | 12.3 °C | 27.7 °C | 16.51 mm |
| July | 15.4 °C | 32.8 °C | 5.59 mm |
| August | 14.9 °C | 32.2 °C | 4.57 mm |
| September | 10.4 °C | 26.8 °C | 6.86 mm |
| October | 5.2 °C | 18.6 °C | 17.53 mm |
| November | 1 °C | 10.4 °C | 22.86 mm |
| December | -1.8 °C | 5 °C | 29.72 mm |
| Annual | 5.8 °C | 18.7 °C | 212.87 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| Average Days With Frost | 75-100 Days |
| Plant Hardiness Zone | Zone 7b : -15°C to -12.2°C |
| Plant Hardiness Zone - 2012 | Zone 7a : -17.8°C to -15°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | BWk - Cold Desert Climate |