Chico, Washington has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 44.2 °F (low) to 61 °F (high). Annual precipitation averages 49.4 Inches. Chico is located in USDA Plant Hardiness Zone 9a. 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 | 36.1 °F | 47.3 °F | 7.72 in. |
| February | 35.9 °F | 49.8 °F | 4.7 in. |
| March | 38.2 °F | 53.9 °F | 5.27 in. |
| April | 41.4 °F | 59.4 °F | 3.38 in. |
| May | 46.8 °F | 66.3 °F | 2.11 in. |
| June | 51.1 °F | 70.3 °F | 1.59 in. |
| July | 54.6 °F | 76.7 °F | 0.83 in. |
| August | 54.8 °F | 77.3 °F | 1.04 in. |
| September | 51.1 °F | 71.9 °F | 1.85 in. |
| October | 45.1 °F | 60.9 °F | 4.68 in. |
| November | 39.3 °F | 51.7 °F | 7.79 in. |
| December | 35.9 °F | 46.4 °F | 8.43 in. |
| Annual | 44.2 °F | 61 °F | 49.39 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 9a : 20°F to 25°F |
| Plant Hardiness Zone - 2012 | Zone 8b : 15°F to 20°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |