Clear Lake, Indiana has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 4 °C (low) to 14.5 °C (high). Annual precipitation averages 964.7 Millimeters. Clear Lake is located in USDA Plant Hardiness Zone 6a. 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 | -8.7 °C | -0.6 °C | 62.23 mm |
| February | -8 °C | 1.2 °C | 54.1 mm |
| March | -3.5 °C | 7.2 °C | 62.23 mm |
| April | 2.6 °C | 14.4 °C | 89.92 mm |
| May | 9.2 °C | 20.8 °C | 106.43 mm |
| June | 14.6 °C | 26 °C | 98.81 mm |
| July | 16.2 °C | 27.9 °C | 95 mm |
| August | 15.2 °C | 26.8 °C | 100.08 mm |
| September | 11 °C | 23.5 °C | 82.55 mm |
| October | 5 °C | 16.4 °C | 77.22 mm |
| November | -0.6 °C | 8.7 °C | 75.44 mm |
| December | -5.3 °C | 2.1 °C | 60.71 mm |
| Annual | 4 °C | 14.5 °C | 964.72 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 6a : -23.3°C to -20.6°C |
| Plant Hardiness Zone - 2012 | Zone 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |