Siletz, Oregon has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 7.1 °C (low) to 16.4 °C (high). Annual precipitation averages 1904.5 Millimeters. Siletz is located in USDA Plant Hardiness Zone 9b. The growing season typically runs from the last frost around Apr. 1 - Apr. 10 through the first frost around Nov. 11 - Nov. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 4.3 °C | 10.7 °C | 297.94 mm |
| February | 3.9 °C | 11.6 °C | 203.2 mm |
| March | 4.4 °C | 12.2 °C | 219.46 mm |
| April | 5.5 °C | 15.3 °C | 150.37 mm |
| May | 7.7 °C | 18.1 °C | 98.04 mm |
| June | 9.6 °C | 19.9 °C | 68.58 mm |
| July | 10.9 °C | 22.4 °C | 18.29 mm |
| August | 10.8 °C | 23.4 °C | 27.94 mm |
| September | 9.9 °C | 22.4 °C | 57.91 mm |
| October | 7.9 °C | 17.4 °C | 154.94 mm |
| November | 5.9 °C | 12.7 °C | 285.75 mm |
| December | 4 °C | 10.1 °C | 322.07 mm |
| Annual | 7.1 °C | 16.4 °C | 1904.49 mm |
| Average First Frost Date | Nov. 11 - Nov. 20 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| Average Days With Frost | 20-30 Days |
| Plant Hardiness Zone | Zone 9b : -3.9°C to -1.1°C |
| Plant Hardiness Zone - 2012 | Zone 9a : -6.7°C to -3.9°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |