Westfield, Wisconsin has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 34.8 °F (low) to 56.1 °F (high). Annual precipitation averages 35.3 Inches. Westfield is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 7.8 °F | 26.2 °F | 1.32 in. |
| February | 10.5 °F | 30.6 °F | 1.21 in. |
| March | 21.3 °F | 42.7 °F | 1.91 in. |
| April | 32.9 °F | 56.4 °F | 3.64 in. |
| May | 45.5 °F | 68.6 °F | 4.2 in. |
| June | 55.6 °F | 78.0 °F | 5.0 in. |
| July | 59.5 °F | 82.4 °F | 4.18 in. |
| August | 57.3 °F | 80.0 °F | 3.99 in. |
| September | 48.9 °F | 72.8 °F | 3.46 in. |
| October | 37.2 °F | 59.5 °F | 2.78 in. |
| November | 25.8 °F | 44.3 °F | 1.98 in. |
| December | 15.0 °F | 31.5 °F | 1.63 in. |
| Annual | 34.8 °F | 56.1 °F | 35.3 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5a : -20°F to -15°F |
| Plant Hardiness Zone - 2012 | Zone 5a : -20°F to -15°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |