Heppner, Oregon has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 38.3 °F (low) to 62.3 °F (high). Annual precipitation averages 13.3 Inches. Heppner 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 | 26.8 °F | 42.1 °F | 1.26 in. |
| February | 28.2 °F | 46.3 °F | 1.1 in. |
| March | 32.1 °F | 53.6 °F | 1.39 in. |
| April | 36.2 °F | 59.7 °F | 1.55 in. |
| May | 42.4 °F | 68.3 °F | 1.74 in. |
| June | 47.5 °F | 75.5 °F | 1.4 in. |
| July | 52.8 °F | 85.9 °F | 0.31 in. |
| August | 52.3 °F | 85.4 °F | 0.28 in. |
| September | 46.0 °F | 76.4 °F | 0.43 in. |
| October | 37.9 °F | 63.0 °F | 1.18 in. |
| November | 31.4 °F | 50.0 °F | 1.41 in. |
| December | 26.2 °F | 41.2 °F | 1.26 in. |
| Annual | 38.3 °F | 62.3 °F | 13.31 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 7a : 0°F to 5°F |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |