Keller, Washington has a Humid Continental Climate - Dry Cool Summer climate (Köppen classification: Dsb). Average annual temperatures range from 3.7 °C (low) to 16.3 °C (high). Annual precipitation averages 284.5 Millimeters. 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 | -4.2 °C | 1.6 °C | 32.77 mm |
| February | -3.3 °C | 5.1 °C | 22.1 mm |
| March | -0.5 °C | 10.9 °C | 28.19 mm |
| April | 2.2 °C | 16.4 °C | 24.89 mm |
| May | 6.4 °C | 21.8 °C | 29.72 mm |
| June | 9.7 °C | 25.7 °C | 25.4 mm |
| July | 13.4 °C | 31.4 °C | 12.45 mm |
| August | 13.2 °C | 31.3 °C | 8.64 mm |
| September | 9 °C | 25.8 °C | 8.89 mm |
| October | 3.6 °C | 16.8 °C | 22.86 mm |
| November | -0.7 °C | 7.4 °C | 30.23 mm |
| December | -4 °C | 1.8 °C | 38.35 mm |
| Annual | 3.7 °C | 16.3 °C | 284.49 mm |
| 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 : -17.8°C to -15°C |
| Plant Hardiness Zone - 2012 | Zone 6b : -20.6°C to -17.8°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dsb - Humid Continental Climate - Dry Cool Summer |