Webb, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 36.3 °F (low) to 56.7 °F (high). Annual precipitation averages 31.9 Inches. 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 | 7.8 °F | 25.4 °F | 0.71 in. |
| February | 11.9 °F | 29.6 °F | 0.84 in. |
| March | 23.9 °F | 42.9 °F | 1.72 in. |
| April | 35.5 °F | 58.1 °F | 3.51 in. |
| May | 48.1 °F | 69.8 °F | 4.32 in. |
| June | 58.7 °F | 79.8 °F | 5.06 in. |
| July | 62.2 °F | 82.9 °F | 3.44 in. |
| August | 59.5 °F | 80.3 °F | 4.21 in. |
| September | 51.0 °F | 74.7 °F | 3.24 in. |
| October | 38.2 °F | 61.5 °F | 2.45 in. |
| November | 25.2 °F | 44.6 °F | 1.46 in. |
| December | 14.0 °F | 30.6 °F | 0.98 in. |
| Annual | 36.3 °F | 56.7 °F | 31.94 in. |
| 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 : -20°F to -15°F |
| Plant Hardiness Zone - 2012 | Zone 5a : -20°F to -15°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |