Pullman, Washington has a Humid Continental Climate - Dry Cool Summer climate (Köppen classification: Dsb). Average annual temperatures range from 37.3 °F (low) to 59 °F (high). Annual precipitation averages 20.5 Inches. Pullman is located in USDA Plant Hardiness Zone 6b. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 26.7 °F | 37.6 °F | 2.6 in. |
| February | 27.8 °F | 41.8 °F | 1.93 in. |
| March | 31.5 °F | 49.1 °F | 2.18 in. |
| April | 35.9 °F | 56.7 °F | 1.86 in. |
| May | 41.8 °F | 65.9 °F | 1.82 in. |
| June | 46.2 °F | 71.9 °F | 1.24 in. |
| July | 49.8 °F | 83.4 °F | 0.44 in. |
| August | 49.8 °F | 84.5 °F | 0.49 in. |
| September | 44.1 °F | 74.9 °F | 0.65 in. |
| October | 37.0 °F | 59.9 °F | 1.76 in. |
| November | 31.3 °F | 45.2 °F | 2.69 in. |
| December | 25.8 °F | 36.5 °F | 2.79 in. |
| Annual | 37.3 °F | 59 °F | 20.45 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 6b : -5°F to 0°F |
| Plant Hardiness Zone - 2012 | Zone 6b : -5°F to 0°F |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Dsb - Humid Continental Climate - Dry Cool Summer |