Tieton, Washington has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 2.7 °C (low) to 15.4 °C (high). Annual precipitation averages 284.2 Millimeters. Tieton is located in USDA Plant Hardiness Zone 7a. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -4.8 °C | 2.6 °C | 49.02 mm |
| February | -3.4 °C | 6.2 °C | 33.53 mm |
| March | -1.1 °C | 10.6 °C | 25.15 mm |
| April | 1.7 °C | 14.9 °C | 17.02 mm |
| May | 5.4 °C | 20 °C | 22.1 mm |
| June | 8.7 °C | 23.7 °C | 15.75 mm |
| July | 12 °C | 28.9 °C | 10.41 mm |
| August | 11.5 °C | 28.6 °C | 5.08 mm |
| September | 7.4 °C | 23.8 °C | 8.89 mm |
| October | 2.1 °C | 15.8 °C | 26.42 mm |
| November | -2.3 °C | 7.7 °C | 24.38 mm |
| December | -5.3 °C | 2 °C | 46.48 mm |
| Annual | 2.7 °C | 15.4 °C | 284.23 mm |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 150-180 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 |