Toppenish, Washington has a Humid Continental Climate - Dry Cool Summer climate (Köppen classification: Dsb). Average annual temperatures range from 38.8 °F (low) to 64 °F (high). Annual precipitation averages 7.7 Inches. Toppenish 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. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 25.4 °F | 39.4 °F | 1.05 in. |
| February | 27.1 °F | 47.2 °F | 0.72 in. |
| March | 32.1 °F | 56.5 °F | 0.58 in. |
| April | 37.2 °F | 64.3 °F | 0.52 in. |
| May | 44.9 °F | 73.4 °F | 0.76 in. |
| June | 50.5 °F | 79.6 °F | 0.6 in. |
| July | 55.9 °F | 88.7 °F | 0.23 in. |
| August | 54.3 °F | 87.6 °F | 0.2 in. |
| September | 46.5 °F | 79.0 °F | 0.22 in. |
| October | 37.2 °F | 64.8 °F | 0.7 in. |
| November | 29.3 °F | 49.5 °F | 0.91 in. |
| December | 24.7 °F | 38.3 °F | 1.23 in. |
| Annual | 38.8 °F | 64 °F | 7.72 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 7a : 0°F to 5°F |
| Plant Hardiness Zone - 2012 | Zone 7a : 0°F to 5°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dsb - Humid Continental Climate - Dry Cool Summer |