Webb, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 2.4 °C (low) to 13.7 °C (high). Annual precipitation averages 811.3 Millimeters. Webb is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -13.4 °C | -3.7 °C | 18.03 mm |
| February | -11.2 °C | -1.3 °C | 21.34 mm |
| March | -4.5 °C | 6.1 °C | 43.69 mm |
| April | 1.9 °C | 14.5 °C | 89.15 mm |
| May | 8.9 °C | 21 °C | 109.73 mm |
| June | 14.8 °C | 26.6 °C | 128.52 mm |
| July | 16.8 °C | 28.3 °C | 87.38 mm |
| August | 15.3 °C | 26.8 °C | 106.93 mm |
| September | 10.6 °C | 23.7 °C | 82.3 mm |
| October | 3.4 °C | 16.4 °C | 62.23 mm |
| November | -3.8 °C | 7 °C | 37.08 mm |
| December | -10 °C | -0.8 °C | 24.89 mm |
| Annual | 2.4 °C | 13.7 °C | 811.27 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5a : -28.9°C to -26.1°C |
| Plant Hardiness Zone - 2012 | Zone 5a : -28.9°C to -26.1°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |