Silverton, Oregon has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 6.4 °C (low) to 17.2 °C (high). Annual precipitation averages 1172.7 Millimeters. Silverton is located in USDA Plant Hardiness Zone 8b. The growing season typically runs from the last frost around Mar. 21 - Mar. 31 through the first frost around Nov. 11 - Nov. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 1.9 °C | 8.5 °C | 169.67 mm |
| February | 2.1 °C | 10.6 °C | 125.22 mm |
| March | 3.3 °C | 13.1 °C | 135.38 mm |
| April | 5 °C | 15.8 °C | 103.63 mm |
| May | 7.8 °C | 19.7 °C | 71.12 mm |
| June | 10.1 °C | 22.7 °C | 45.72 mm |
| July | 12.2 °C | 27.4 °C | 10.41 mm |
| August | 12 °C | 27.6 °C | 13.21 mm |
| September | 10 °C | 24.4 °C | 40.13 mm |
| October | 6.7 °C | 17.6 °C | 98.3 mm |
| November | 3.8 °C | 11.5 °C | 172.72 mm |
| December | 1.6 °C | 7.9 °C | 187.2 mm |
| Annual | 6.4 °C | 17.2 °C | 1172.71 mm |
| Average First Frost Date | Nov. 11 - Nov. 20 |
| Average Last Frost Date | Mar. 21 - Mar. 31 |
| Average Days With Frost | 40-50 Days |
| Plant Hardiness Zone | Zone 8b : -9.4°C to -6.7°C |
| Plant Hardiness Zone - 2012 | Zone 8b : -9.4°C to -6.7°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |