Big Lake, Washington has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 42.7 °F (low) to 59.8 °F (high). Annual precipitation averages 39.5 Inches. Big Lake 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 Nov. 1 - Nov. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 34.7 °F | 46.1 °F | 4.97 in. |
| February | 34.6 °F | 48.4 °F | 3.5 in. |
| March | 37.2 °F | 52.6 °F | 3.9 in. |
| April | 40.7 °F | 58.6 °F | 3.2 in. |
| May | 45.6 °F | 65.1 °F | 2.86 in. |
| June | 49.8 °F | 69.1 °F | 2.0 in. |
| July | 52.6 °F | 75.0 °F | 1.01 in. |
| August | 52.6 °F | 76.0 °F | 1.23 in. |
| September | 49.0 °F | 70.2 °F | 2.14 in. |
| October | 43.0 °F | 60.1 °F | 4.2 in. |
| November | 38.1 °F | 50.7 °F | 5.8 in. |
| December | 34.3 °F | 45.1 °F | 4.65 in. |
| Annual | 42.7 °F | 59.8 °F | 39.46 in. |
| Average First Frost Date | Nov. 1 - Nov. 10 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| 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 |