Silvana, Washington has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 42.1 °F (low) to 59.6 °F (high). Annual precipitation averages 38.3 Inches. Silvana 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 Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 34.6 °F | 46.4 °F | 4.56 in. |
| February | 34.2 °F | 48.7 °F | 3.44 in. |
| March | 36.7 °F | 52.8 °F | 3.98 in. |
| April | 40.3 °F | 58.2 °F | 3.3 in. |
| May | 45.2 °F | 64.6 °F | 2.58 in. |
| June | 49.2 °F | 68.3 °F | 1.95 in. |
| July | 51.5 °F | 74.3 °F | 1.03 in. |
| August | 51.5 °F | 75.1 °F | 1.09 in. |
| September | 47.9 °F | 70.2 °F | 2.05 in. |
| October | 42.2 °F | 59.7 °F | 3.8 in. |
| November | 37.6 °F | 51.1 °F | 5.58 in. |
| December | 34.2 °F | 45.4 °F | 4.93 in. |
| Annual | 42.1 °F | 59.6 °F | 38.29 in. |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Mar. 21 - Mar. 31 |
| Average Days With Frost | 40-50 Days |
| Plant Hardiness Zone | Zone 8b : 15°F to 20°F |
| Plant Hardiness Zone - 2012 | Zone 8b : 15°F to 20°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |