Webster, Wisconsin has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from -0.4 °C (low) to 11.7 °C (high). Annual precipitation averages 808.7 Millimeters. Webster is located in USDA Plant Hardiness Zone 4a. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -17 °C | -5.7 °C | 20.83 mm |
| February | -15.2 °C | -2.7 °C | 23.11 mm |
| March | -8.2 °C | 4.3 °C | 37.85 mm |
| April | -1.2 °C | 12 °C | 69.85 mm |
| May | 5.9 °C | 19.6 °C | 97.03 mm |
| June | 11.6 °C | 24.5 °C | 111 mm |
| July | 14.1 °C | 26.8 °C | 107.44 mm |
| August | 12.8 °C | 25.7 °C | 102.87 mm |
| September | 8.2 °C | 21.3 °C | 86.11 mm |
| October | 1.7 °C | 13.4 °C | 80.26 mm |
| November | -5.2 °C | 4.4 °C | 41.4 mm |
| December | -12.4 °C | -2.8 °C | 30.99 mm |
| Annual | -0.4 °C | 11.7 °C | 808.74 mm |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 4a : -34.4°C to -31.7°C |
| Plant Hardiness Zone - 2012 | Zone 3b : -37.2°C to -34.4°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |