Soap Lake, Washington has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 4.2 °C (low) to 17.2 °C (high). Annual precipitation averages 201.4 Millimeters. Soap Lake is located in USDA Plant Hardiness Zone 7a. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -4.3 °C | 2.4 °C | 25.65 mm |
| February | -2.8 °C | 6.6 °C | 18.29 mm |
| March | -0.1 °C | 12.3 °C | 18.8 mm |
| April | 3.1 °C | 17.6 °C | 15.24 mm |
| May | 7.8 °C | 23 °C | 15.49 mm |
| June | 11.3 °C | 26.8 °C | 17.02 mm |
| July | 14.7 °C | 31.9 °C | 7.11 mm |
| August | 14 °C | 31.3 °C | 4.32 mm |
| September | 9.3 °C | 26 °C | 6.86 mm |
| October | 3.6 °C | 17.6 °C | 17.02 mm |
| November | -1.3 °C | 8.4 °C | 23.37 mm |
| December | -4.4 °C | 2.4 °C | 32.26 mm |
| Annual | 4.2 °C | 17.2 °C | 201.43 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 7a : -17.8°C to -15°C |
| Plant Hardiness Zone - 2012 | Zone 6b : -20.6°C to -17.8°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |