Kettle Falls, Washington has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 36 °F (low) to 59.3 °F (high). Annual precipitation averages 19.5 Inches. Kettle Falls is located in USDA Plant Hardiness Zone 6b. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 22.6 °F | 33.3 °F | 2.33 in. |
| February | 23.5 °F | 40.0 °F | 1.49 in. |
| March | 28.5 °F | 50.0 °F | 2.01 in. |
| April | 33.9 °F | 60.0 °F | 1.49 in. |
| May | 41.6 °F | 69.8 °F | 1.69 in. |
| June | 47.5 °F | 75.3 °F | 1.83 in. |
| July | 52.3 °F | 85.9 °F | 0.86 in. |
| August | 51.3 °F | 86.4 °F | 0.55 in. |
| September | 44.0 °F | 75.9 °F | 0.78 in. |
| October | 35.1 °F | 58.7 °F | 1.42 in. |
| November | 28.7 °F | 42.5 °F | 2.44 in. |
| December | 22.6 °F | 33.3 °F | 2.64 in. |
| Annual | 36 °F | 59.3 °F | 19.53 in. |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 6b : -5°F to 0°F |
| Plant Hardiness Zone - 2012 | Zone 6a : -10°F to -5°F |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |