Ephrata, Washington has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 39.2 °F (low) to 62.2 °F (high). Annual precipitation averages 8 Inches. Ephrata 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. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 23.9 °F | 36.0 °F | 0.96 in. |
| February | 26.8 °F | 43.2 °F | 0.71 in. |
| March | 31.6 °F | 53.5 °F | 0.75 in. |
| April | 37.1 °F | 62.7 °F | 0.67 in. |
| May | 45.3 °F | 72.5 °F | 0.65 in. |
| June | 51.4 °F | 79.3 °F | 0.66 in. |
| July | 57.7 °F | 88.6 °F | 0.29 in. |
| August | 56.7 °F | 87.5 °F | 0.18 in. |
| September | 48.6 °F | 78.2 °F | 0.25 in. |
| October | 38.4 °F | 62.9 °F | 0.67 in. |
| November | 29.5 °F | 46.5 °F | 0.93 in. |
| December | 23.7 °F | 35.8 °F | 1.24 in. |
| Annual | 39.2 °F | 62.2 °F | 7.96 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 7a : 0°F to 5°F |
| Plant Hardiness Zone - 2012 | Zone 6b : -5°F to 0°F |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |