Siletz, Oregon has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 44.7 °F (low) to 61.4 °F (high). Annual precipitation averages 75 Inches. 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 | 39.8 °F | 51.2 °F | 11.73 in. |
| February | 39.1 °F | 52.9 °F | 8.0 in. |
| March | 40.0 °F | 53.9 °F | 8.64 in. |
| April | 41.9 °F | 59.6 °F | 5.92 in. |
| May | 45.8 °F | 64.5 °F | 3.86 in. |
| June | 49.2 °F | 67.8 °F | 2.7 in. |
| July | 51.6 °F | 72.4 °F | 0.72 in. |
| August | 51.5 °F | 74.2 °F | 1.1 in. |
| September | 49.9 °F | 72.4 °F | 2.28 in. |
| October | 46.3 °F | 63.3 °F | 6.1 in. |
| November | 42.6 °F | 54.9 °F | 11.25 in. |
| December | 39.2 °F | 50.1 °F | 12.68 in. |
| Annual | 44.7 °F | 61.4 °F | 74.98 in. |
| 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 : 25°F to 20°F |
| Plant Hardiness Zone - 2012 | Zone 9a : 20°F to 25°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |