Kittitas, Washington has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 2.3 °C (low) to 15.5 °C (high). Annual precipitation averages 234.9 Millimeters. Kittitas is located in USDA Plant Hardiness Zone 6b. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -5.6 °C | 1.9 °C | 32 mm |
| February | -4.2 °C | 5.9 °C | 16.76 mm |
| March | -1.8 °C | 11 °C | 19.81 mm |
| April | 1.1 °C | 15.3 °C | 20.07 mm |
| May | 5.4 °C | 20.3 °C | 19.3 mm |
| June | 8.9 °C | 23.9 °C | 14.22 mm |
| July | 12.1 °C | 29.3 °C | 7.87 mm |
| August | 11.6 °C | 29.1 °C | 4.32 mm |
| September | 7 °C | 24.3 °C | 10.41 mm |
| October | 1.7 °C | 16.2 °C | 18.8 mm |
| November | -2.7 °C | 7.5 °C | 25.65 mm |
| December | -5.7 °C | 1.8 °C | 45.72 mm |
| Annual | 2.3 °C | 15.5 °C | 234.93 mm |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 150-180 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 | BSk - Cold Semi-Arid Climate |