Lake Cavanaugh, Washington has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 41 °F (low) to 57 °F (high). Annual precipitation averages 69.3 Inches. Lake Cavanaugh is located in USDA Plant Hardiness Zone 8b. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 32.2 °F | 41.5 °F | 8.54 in. |
| February | 32.6 °F | 44.3 °F | 6.74 in. |
| March | 34.2 °F | 48.8 °F | 7.35 in. |
| April | 37.8 °F | 55.5 °F | 3.9 in. |
| May | 43.6 °F | 63.5 °F | 3.39 in. |
| June | 47.6 °F | 67.8 °F | 3.51 in. |
| July | 52.4 °F | 74.7 °F | 1.79 in. |
| August | 53.4 °F | 75.8 °F | 1.62 in. |
| September | 48.0 °F | 68.8 °F | 3.63 in. |
| October | 41.9 °F | 55.6 °F | 7.68 in. |
| November | 35.9 °F | 46.0 °F | 11.19 in. |
| December | 32.4 °F | 41.4 °F | 9.98 in. |
| Annual | 41 °F | 57 °F | 69.32 in. |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 50-75 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 |