Wilsonville, Oregon has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 6.9 °C (low) to 17.5 °C (high). Annual precipitation averages 1082.6 Millimeters. Wilsonville is located in USDA Plant Hardiness Zone 9a. The growing season typically runs from the last frost around Mar. 1 - Mar. 10 through the first frost around Nov. 11 - Nov. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 2.3 °C | 8.6 °C | 160.27 mm |
| February | 2.4 °C | 10.7 °C | 112.27 mm |
| March | 3.7 °C | 13.3 °C | 123.95 mm |
| April | 5.5 °C | 16.1 °C | 85.34 mm |
| May | 8.4 °C | 20.1 °C | 66.29 mm |
| June | 10.8 °C | 23 °C | 41.66 mm |
| July | 12.9 °C | 27.6 °C | 9.4 mm |
| August | 12.9 °C | 27.8 °C | 11.43 mm |
| September | 10.7 °C | 24.6 °C | 37.85 mm |
| October | 7.2 °C | 17.8 °C | 97.03 mm |
| November | 4.2 °C | 11.7 °C | 154.94 mm |
| December | 2 °C | 8.1 °C | 182.12 mm |
| Annual | 6.9 °C | 17.5 °C | 1082.55 mm |
| Average First Frost Date | Nov. 11 - Nov. 20 |
| Average Last Frost Date | Mar. 1 - Mar. 10 |
| Average Days With Frost | 20-30 Days |
| Plant Hardiness Zone | Zone 9a : -6.7°C to -3.9°C |
| Plant Hardiness Zone - 2012 | Zone 8b : -9.4°C to -6.7°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |