Medical Lake, Washington has a Humid Continental Climate - Dry Cool Summer climate (Köppen classification: Dsb). Average annual temperatures range from 2.4 °C (low) to 14.1 °C (high). Annual precipitation averages 454.4 Millimeters. 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 | -4.9 °C | 1.1 °C | 55.88 mm |
| February | -4.1 °C | 4 °C | 38.35 mm |
| March | -1.6 °C | 8.9 °C | 50.55 mm |
| April | 1.2 °C | 13.4 °C | 34.04 mm |
| May | 5.3 °C | 18.8 °C | 39.88 mm |
| June | 8.6 °C | 22.4 °C | 33.78 mm |
| July | 11.6 °C | 28.6 °C | 11.43 mm |
| August | 11.2 °C | 28.4 °C | 11.68 mm |
| September | 6.8 °C | 22.9 °C | 13.21 mm |
| October | 1.7 °C | 14.4 °C | 38.35 mm |
| November | -2.1 °C | 5.9 °C | 57.4 mm |
| December | -5.1 °C | 0.8 °C | 69.85 mm |
| Annual | 2.4 °C | 14.1 °C | 454.4 mm |
| 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 : -20.6°C to -17.8°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 |