Lake Koshkonong, Wisconsin has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 37.8 °F (low) to 57.3 °F (high). Annual precipitation averages 36.7 Inches. 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 °F | 27.7 °F | 1.55 in. |
| February | 14.3 °F | 31.6 °F | 1.55 in. |
| March | 25.1 °F | 43.8 °F | 2.05 in. |
| April | 36.2 °F | 57.0 °F | 3.68 in. |
| May | 47.9 °F | 69.4 °F | 4.15 in. |
| June | 57.8 °F | 79.3 °F | 5.19 in. |
| July | 61.9 °F | 82.9 °F | 4.0 in. |
| August | 60.1 °F | 81.0 °F | 4.11 in. |
| September | 51.7 °F | 74.2 °F | 3.46 in. |
| October | 40.1 °F | 61.1 °F | 2.9 in. |
| November | 28.9 °F | 45.9 °F | 2.24 in. |
| December | 18.5 °F | 33.2 °F | 1.81 in. |
| Annual | 37.8 °F | 57.3 °F | 36.69 in. |
| 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 : -15°F to -10°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 |