Maxwell, California has a Hot-Summer Mediterranean Climate climate (Köppen classification: Csa). Average annual temperatures range from 49 °F (low) to 74.9 °F (high). Annual precipitation averages 18 Inches. Maxwell is located in USDA Plant Hardiness Zone 9b. The growing season typically runs from the last frost around Feb. 21 - Feb. 29 through the first frost around Nov. 21 - Nov. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 38.9 °F | 56.2 °F | 3.71 in. |
| February | 41.1 °F | 61.4 °F | 3.37 in. |
| March | 43.5 °F | 66.8 °F | 2.35 in. |
| April | 46.0 °F | 72.8 °F | 1.21 in. |
| May | 53.3 °F | 80.6 °F | 0.78 in. |
| June | 58.8 °F | 87.9 °F | 0.23 in. |
| July | 61.1 °F | 92.3 °F | 0.02 in. |
| August | 59.5 °F | 91.5 °F | 0.05 in. |
| September | 55.9 °F | 88.6 °F | 0.16 in. |
| October | 49.6 °F | 79.4 °F | 0.83 in. |
| November | 42.2 °F | 65.2 °F | 1.84 in. |
| December | 38.1 °F | 56.0 °F | 3.42 in. |
| Annual | 49 °F | 74.9 °F | 17.97 in. |
| Average First Frost Date | Nov. 21 - Nov. 30 |
| Average Last Frost Date | Feb. 21 - Feb. 29 |
| Average Days With Frost | 20-30 Days |
| Plant Hardiness Zone | Zone 9b : 25°F to 20°F |
| Plant Hardiness Zone - 2012 | Zone 9b : 25°F to 20°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Csa - Hot-Summer Mediterranean Climate |