Cottage Lake, Washington has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 6.5 °C (low) to 15.7 °C (high). Annual precipitation averages 1187.7 Millimeters. Cottage Lake 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. 1 - Nov. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 1.9 °C | 8.2 °C | 159 mm |
| February | 1.9 °C | 9.7 °C | 114.3 mm |
| March | 3.2 °C | 11.9 °C | 117.86 mm |
| April | 5.1 °C | 14.7 °C | 103.38 mm |
| May | 8.1 °C | 18.4 °C | 73.66 mm |
| June | 10.4 °C | 20.8 °C | 65.02 mm |
| July | 12.4 °C | 24.6 °C | 26.67 mm |
| August | 12.4 °C | 24.9 °C | 26.16 mm |
| September | 10.3 °C | 21.6 °C | 57.4 mm |
| October | 6.8 °C | 15.6 °C | 110.49 mm |
| November | 3.8 °C | 10.7 °C | 176.78 mm |
| December | 1.7 °C | 7.6 °C | 156.97 mm |
| Annual | 6.5 °C | 15.7 °C | 1187.69 mm |
| Average First Frost Date | Nov. 1 - Nov. 10 |
| 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 | Normal |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |