Millersburg, Oregon has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 42.9 °F (low) to 63.7 °F (high). Annual precipitation averages 42.4 Inches. Millersburg is located in USDA Plant Hardiness Zone 8b. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 35.1 °F | 47.5 °F | 6.07 in. |
| February | 35.2 °F | 51.5 °F | 4.6 in. |
| March | 37.4 °F | 56.2 °F | 4.87 in. |
| April | 40.4 °F | 61.4 °F | 3.52 in. |
| May | 45.4 °F | 68.1 °F | 2.42 in. |
| June | 49.5 °F | 73.4 °F | 1.57 in. |
| July | 53.2 °F | 82.1 °F | 0.33 in. |
| August | 52.8 °F | 82.7 °F | 0.44 in. |
| September | 49.0 °F | 76.9 °F | 1.45 in. |
| October | 43.0 °F | 64.7 °F | 3.6 in. |
| November | 38.5 °F | 53.1 °F | 6.21 in. |
| December | 34.7 °F | 46.5 °F | 7.31 in. |
| Annual | 42.9 °F | 63.7 °F | 42.39 in. |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 50-75 Days |
| Plant Hardiness Zone | Zone 8b : 15°F to 20°F |
| Plant Hardiness Zone - 2012 | Zone 8b : 15°F to 20°F |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |