Loon Lake, Washington has a Humid Continental Climate - Dry Cool Summer climate (Köppen classification: Dsb). Average annual temperatures range from 34.1 °F (low) to 57.7 °F (high). Annual precipitation averages 25.3 Inches. Loon Lake is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Sep.11 - Sep. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 21.1 °F | 33.9 °F | 3.14 in. |
| February | 22.1 °F | 39.6 °F | 2.11 in. |
| March | 27.1 °F | 48.2 °F | 2.84 in. |
| April | 31.9 °F | 56.6 °F | 1.8 in. |
| May | 39.4 °F | 66.5 °F | 2.16 in. |
| June | 45.0 °F | 72.7 °F | 1.99 in. |
| July | 50.0 °F | 83.7 °F | 0.65 in. |
| August | 49.2 °F | 84.1 °F | 0.5 in. |
| September | 42.0 °F | 73.9 °F | 0.8 in. |
| October | 33.3 °F | 57.8 °F | 2.0 in. |
| November | 27.1 °F | 42.2 °F | 3.11 in. |
| December | 21.3 °F | 33.3 °F | 4.24 in. |
| Annual | 34.1 °F | 57.7 °F | 25.34 in. |
| Average First Frost Date | Sep.11 - Sep. 20 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 6a : -10°F to -5°F |
| Plant Hardiness Zone - 2012 | Zone 6a : -10°F to -5°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dsb - Humid Continental Climate - Dry Cool Summer |