Rowena, Oregon has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 6.4 °C (low) to 18.4 °C (high). Annual precipitation averages 508.3 Millimeters. Rowena is located in USDA Plant Hardiness Zone 8a. The growing season typically runs from the last frost around Apr. 1 - Apr. 10 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -0.1 °C | 6.2 °C | 87.63 mm |
| February | 0.4 °C | 9.5 °C | 54.36 mm |
| March | 2.6 °C | 13.8 °C | 52.58 mm |
| April | 5.3 °C | 17.7 °C | 31.5 mm |
| May | 8.8 °C | 22.6 °C | 23.62 mm |
| June | 11.7 °C | 25.8 °C | 15.24 mm |
| July | 14.7 °C | 30.7 °C | 4.32 mm |
| August | 14.3 °C | 30.9 °C | 6.35 mm |
| September | 10.4 °C | 26.9 °C | 11.43 mm |
| October | 6.1 °C | 19.3 °C | 40.39 mm |
| November | 2.2 °C | 10.9 °C | 78.49 mm |
| December | -0.1 °C | 6.1 °C | 102.36 mm |
| Annual | 6.4 °C | 18.4 °C | 508.27 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| Average Days With Frost | 75-100 Days |
| Plant Hardiness Zone | Zone 8a : -12.2°C to -9.4°C |
| Plant Hardiness Zone - 2012 | Zone 8a : -12.2°C to -9.4°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |