Koontz Lake, Indiana has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 40 °F (low) to 59.5 °F (high). Annual precipitation averages 40.5 Inches. Koontz Lake is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 16.4 °F | 31.8 °F | 2.58 in. |
| February | 19.1 °F | 35.7 °F | 2.3 in. |
| March | 27.6 °F | 46.9 °F | 2.38 in. |
| April | 37.9 °F | 59.7 °F | 3.61 in. |
| May | 49.5 °F | 70.9 °F | 4.39 in. |
| June | 59.3 °F | 80.0 °F | 4.4 in. |
| July | 62.1 °F | 83.0 °F | 4.38 in. |
| August | 60.2 °F | 81.3 °F | 4.19 in. |
| September | 52.5 °F | 75.7 °F | 3.37 in. |
| October | 41.6 °F | 63.3 °F | 3.45 in. |
| November | 31.7 °F | 48.8 °F | 2.99 in. |
| December | 22.6 °F | 37.1 °F | 2.44 in. |
| Annual | 40 °F | 59.5 °F | 40.48 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 5b : -15°F to -10°F |
| Plant Hardiness Zone - 2012 | Zone 5b : -15°F to -10°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |