Lannon, Wisconsin has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 2.8 °C (low) to 13.3 °C (high). Annual precipitation averages 926.6 Millimeters. Lannon is located in USDA Plant Hardiness Zone 5b. 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 | -11.2 °C | -2.4 °C | 46.99 mm |
| February | -9.6 °C | -0.4 °C | 43.69 mm |
| March | -4.4 °C | 5.8 °C | 55.12 mm |
| April | 1.6 °C | 12.8 °C | 99.82 mm |
| May | 7.6 °C | 19.4 °C | 104.14 mm |
| June | 13 °C | 24.7 °C | 116.84 mm |
| July | 15.9 °C | 27.6 °C | 105.92 mm |
| August | 15 °C | 26.5 °C | 91.19 mm |
| September | 10.6 °C | 22.6 °C | 80.26 mm |
| October | 4.3 °C | 15.4 °C | 74.17 mm |
| November | -1.8 °C | 7.4 °C | 55.12 mm |
| December | -7.5 °C | 0.6 °C | 53.34 mm |
| Annual | 2.8 °C | 13.3 °C | 926.6 mm |
| 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 5b : -26.1°C to -23.3°C |
| Plant Hardiness Zone - 2012 | Zone 5a : -28.9°C to -26.1°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |