Trout Lake, Washington has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 2.1 °C (low) to 14.9 °C (high). Annual precipitation averages 1142.5 Millimeters. Trout Lake is located in USDA Plant Hardiness Zone 7a. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Sep.11 - Sep. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -3.3 °C | 3.8 °C | 183.64 mm |
| February | -2.8 °C | 6 °C | 134.37 mm |
| March | -1.1 °C | 9.5 °C | 137.41 mm |
| April | 0.7 °C | 13.3 °C | 68.07 mm |
| May | 4 °C | 19.2 °C | 46.23 mm |
| June | 6.7 °C | 21.4 °C | 28.19 mm |
| July | 9.1 °C | 27.4 °C | 8.89 mm |
| August | 8.9 °C | 28.6 °C | 10.92 mm |
| September | 5.3 °C | 23.2 °C | 27.18 mm |
| October | 1.8 °C | 15.3 °C | 100.33 mm |
| November | -1.1 °C | 7.5 °C | 178.82 mm |
| December | -3.5 °C | 3.2 °C | 218.44 mm |
| Annual | 2.1 °C | 14.9 °C | 1142.49 mm |
| Average First Frost Date | Sep.11 - Sep. 20 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 7a : -17.8°C to -15°C |
| Plant Hardiness Zone - 2012 | Zone 6b : -20.6°C to -17.8°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |