Asotin, Washington has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 6.4 °C (low) to 18.7 °C (high). Annual precipitation averages 320.5 Millimeters. Asotin is located in USDA Plant Hardiness Zone 7b. The growing season typically runs from the last frost around Mar. 21 - Mar. 31 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -0.5 °C | 6.2 °C | 29.72 mm |
| February | -0.1 °C | 9.1 °C | 31.75 mm |
| March | 2.2 °C | 13.6 °C | 34.04 mm |
| April | 5.1 °C | 17.9 °C | 29.46 mm |
| May | 8.8 °C | 22.9 °C | 36.32 mm |
| June | 12.2 °C | 26.7 °C | 28.7 mm |
| July | 15.5 °C | 33.4 °C | 13.21 mm |
| August | 15.3 °C | 33.2 °C | 11.68 mm |
| September | 11.4 °C | 27.6 °C | 13.46 mm |
| October | 6.1 °C | 18.6 °C | 26.92 mm |
| November | 2 °C | 10.3 °C | 35.05 mm |
| December | -0.9 °C | 5.4 °C | 30.23 mm |
| Annual | 6.4 °C | 18.7 °C | 320.54 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Mar. 21 - Mar. 31 |
| Average Days With Frost | 75-100 Days |
| Plant Hardiness Zone | Zone 7b : -15°C to -12.2°C |
| Plant Hardiness Zone - 2012 | Zone 7b : -15°C to -12.2°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |