Merrill, Oregon has a Humid Continental Climate - Dry Cool Summer climate (Köppen classification: Dsb). Average annual temperatures range from 31.6 °F (low) to 61.2 °F (high). Annual precipitation averages 11.7 Inches. Merrill is located in USDA Plant Hardiness Zone 6b. The growing season typically runs from the last frost around May 21 - May 31 through the first frost around Sep.11 - Sep. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 21.3 °F | 41.3 °F | 1.46 in. |
| February | 23.5 °F | 45.6 °F | 1.04 in. |
| March | 26.5 °F | 51.3 °F | 1.2 in. |
| April | 29.2 °F | 57.0 °F | 1.0 in. |
| May | 36.0 °F | 66.3 °F | 1.44 in. |
| June | 40.8 °F | 74.4 °F | 0.69 in. |
| July | 46.3 °F | 84.3 °F | 0.27 in. |
| August | 44.0 °F | 83.4 °F | 0.27 in. |
| September | 37.1 °F | 77.0 °F | 0.41 in. |
| October | 29.4 °F | 64.1 °F | 0.81 in. |
| November | 24.4 °F | 49.1 °F | 1.32 in. |
| December | 20.2 °F | 40.1 °F | 1.78 in. |
| Annual | 31.6 °F | 61.2 °F | 11.69 in. |
| Average First Frost Date | Sep.11 - Sep. 20 |
| Average Last Frost Date | May 21 - May 31 |
| Average Days With Frost | 150-180 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 | Abnormally Dry |
| Köppen Climate Classification | Dsb - Humid Continental Climate - Dry Cool Summer |