Keller, Washington has a Humid Continental Climate - Dry Cool Summer climate (Köppen classification: Dsb). Average annual temperatures range from 38.7 °F (low) to 61.4 °F (high). Annual precipitation averages 11.2 Inches. Keller is located in USDA Plant Hardiness Zone 7a. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 24.4 °F | 34.9 °F | 1.29 in. |
| February | 26.0 °F | 41.1 °F | 0.87 in. |
| March | 31.1 °F | 51.6 °F | 1.11 in. |
| April | 36.0 °F | 61.5 °F | 0.98 in. |
| May | 43.6 °F | 71.3 °F | 1.17 in. |
| June | 49.4 °F | 78.3 °F | 1.0 in. |
| July | 56.1 °F | 88.6 °F | 0.49 in. |
| August | 55.7 °F | 88.3 °F | 0.34 in. |
| September | 48.2 °F | 78.4 °F | 0.35 in. |
| October | 38.5 °F | 62.3 °F | 0.9 in. |
| November | 30.8 °F | 45.3 °F | 1.19 in. |
| December | 24.8 °F | 35.2 °F | 1.51 in. |
| Annual | 38.7 °F | 61.4 °F | 11.2 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 7a : 0°F to 5°F |
| Plant Hardiness Zone - 2012 | Zone 6b : -5°F to 0°F |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dsb - Humid Continental Climate - Dry Cool Summer |