Lake Koshkonong, Wisconsin has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 3.2 °C (low) to 14 °C (high). Annual precipitation averages 931.9 Millimeters. Lake Koshkonong 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. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -11.4 °C | -2.4 °C | 39.37 mm |
| February | -9.8 °C | -0.2 °C | 39.37 mm |
| March | -3.8 °C | 6.6 °C | 52.07 mm |
| April | 2.3 °C | 13.9 °C | 93.47 mm |
| May | 8.8 °C | 20.8 °C | 105.41 mm |
| June | 14.3 °C | 26.3 °C | 131.83 mm |
| July | 16.6 °C | 28.3 °C | 101.6 mm |
| August | 15.6 °C | 27.2 °C | 104.39 mm |
| September | 10.9 °C | 23.4 °C | 87.88 mm |
| October | 4.5 °C | 16.2 °C | 73.66 mm |
| November | -1.7 °C | 7.7 °C | 56.9 mm |
| December | -7.5 °C | 0.7 °C | 45.97 mm |
| Annual | 3.2 °C | 14 °C | 931.92 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 125-150 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 | Abnormally Dry |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |