Maxwell, California has a Hot-Summer Mediterranean Climate climate (Köppen classification: Csa). Average annual temperatures range from 9.5 °C (low) to 23.8 °C (high). Annual precipitation averages 456.4 Millimeters. 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 | 3.8 °C | 13.4 °C | 94.23 mm |
| February | 5.1 °C | 16.3 °C | 85.6 mm |
| March | 6.4 °C | 19.3 °C | 59.69 mm |
| April | 7.8 °C | 22.7 °C | 30.73 mm |
| May | 11.8 °C | 27 °C | 19.81 mm |
| June | 14.9 °C | 31.1 °C | 5.84 mm |
| July | 16.2 °C | 33.5 °C | 0.51 mm |
| August | 15.3 °C | 33.1 °C | 1.27 mm |
| September | 13.3 °C | 31.4 °C | 4.06 mm |
| October | 9.8 °C | 26.3 °C | 21.08 mm |
| November | 5.7 °C | 18.4 °C | 46.74 mm |
| December | 3.4 °C | 13.3 °C | 86.87 mm |
| Annual | 9.5 °C | 23.8 °C | 456.43 mm |
| 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 : -3.9°C to -1.1°C |
| Plant Hardiness Zone - 2012 | Zone 9b : -3.9°C to -1.1°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Csa - Hot-Summer Mediterranean Climate |