Sisco Heights, Washington has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 6.4 °C (low) to 15.1 °C (high). Annual precipitation averages 1305.1 Millimeters. Sisco Heights is located in USDA Plant Hardiness Zone 8b. The growing season typically runs from the last frost around Apr. 1 - Apr. 10 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 1.8 °C | 7.5 °C | 171.7 mm |
| February | 1.8 °C | 8.9 °C | 122.17 mm |
| March | 3.2 °C | 11.1 °C | 139.7 mm |
| April | 5.1 °C | 14.3 °C | 107.95 mm |
| May | 7.9 °C | 18 °C | 78.49 mm |
| June | 10.1 °C | 20.1 °C | 76.45 mm |
| July | 12.1 °C | 23.7 °C | 30.48 mm |
| August | 12.4 °C | 24.2 °C | 29.72 mm |
| September | 10.3 °C | 21.3 °C | 71.37 mm |
| October | 6.9 °C | 15.1 °C | 137.16 mm |
| November | 3.6 °C | 10 °C | 180.09 mm |
| December | 1.7 °C | 7.2 °C | 159.77 mm |
| Annual | 6.4 °C | 15.1 °C | 1305.05 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| 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 | Normal |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |