Snoqualmie Pass, Washington has a Continental Subarctic - Cold Dry Summer climate (Köppen classification: Dsc). Average annual temperatures range from 2.2 °C (low) to 11 °C (high). Annual precipitation averages 2258.3 Millimeters. Snoqualmie Pass is located in USDA Plant Hardiness Zone 7b. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -3.2 °C | 1.9 °C | 370.08 mm |
| February | -3 °C | 3.6 °C | 219.96 mm |
| March | -1.8 °C | 6.3 °C | 290.07 mm |
| April | 0.1 °C | 9.1 °C | 167.89 mm |
| May | 3.2 °C | 13.8 °C | 100.33 mm |
| June | 6.1 °C | 16.9 °C | 70.61 mm |
| July | 9.3 °C | 22 °C | 37.34 mm |
| August | 9.6 °C | 22.6 °C | 40.64 mm |
| September | 6.9 °C | 18.8 °C | 105.66 mm |
| October | 3.1 °C | 11.6 °C | 201.42 mm |
| November | -0.7 °C | 4.8 °C | 351.28 mm |
| December | -3.5 °C | 1.1 °C | 303.02 mm |
| Annual | 2.2 °C | 11 °C | 2258.3 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 7b : -15°C to -12.2°C |
| Plant Hardiness Zone - 2012 | Zone 7a : -17.8°C to -15°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dsc - Continental Subarctic - Cold Dry Summer |