Medical Lake, Washington has a Humid Continental Climate - Dry Cool Summer climate (Köppen classification: Dsb). Average annual temperatures range from 36.3 °F (low) to 57.5 °F (high). Annual precipitation averages 17.9 Inches. Medical Lake 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 Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 23.1 °F | 33.9 °F | 2.2 in. |
| February | 24.6 °F | 39.2 °F | 1.51 in. |
| March | 29.2 °F | 48.1 °F | 1.99 in. |
| April | 34.1 °F | 56.2 °F | 1.34 in. |
| May | 41.5 °F | 65.8 °F | 1.57 in. |
| June | 47.4 °F | 72.4 °F | 1.33 in. |
| July | 52.8 °F | 83.4 °F | 0.45 in. |
| August | 52.2 °F | 83.2 °F | 0.46 in. |
| September | 44.3 °F | 73.3 °F | 0.52 in. |
| October | 35.0 °F | 58.0 °F | 1.51 in. |
| November | 28.3 °F | 42.7 °F | 2.26 in. |
| December | 22.9 °F | 33.5 °F | 2.75 in. |
| Annual | 36.3 °F | 57.5 °F | 17.89 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| 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 6b : -5°F to 0°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dsb - Humid Continental Climate - Dry Cool Summer |