Williams, Arizona has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 34.5 °F (low) to 64.3 °F (high). Annual precipitation averages 20.8 Inches. Williams is located in USDA Plant Hardiness Zone 7a. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 20.1 °F | 45.6 °F | 2.13 in. |
| February | 22.0 °F | 47.9 °F | 2.46 in. |
| March | 26.1 °F | 54.2 °F | 1.97 in. |
| April | 30.3 °F | 61.1 °F | 0.74 in. |
| May | 37.5 °F | 70.2 °F | 0.57 in. |
| June | 45.5 °F | 81.7 °F | 0.37 in. |
| July | 53.3 °F | 84.4 °F | 2.91 in. |
| August | 52.3 °F | 81.8 °F | 3.2 in. |
| September | 45.5 °F | 76.7 °F | 1.59 in. |
| October | 34.8 °F | 66.7 °F | 1.51 in. |
| November | 26.4 °F | 55.0 °F | 1.3 in. |
| December | 19.9 °F | 45.7 °F | 2.0 in. |
| Annual | 34.5 °F | 64.3 °F | 20.75 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 7a : 0°F to 5°F |
| Plant Hardiness Zone - 2012 | Zone 7a : 0°F to 5°F |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |