Simonton Lake, Indiana has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 4.7 °C (low) to 14.9 °C (high). Annual precipitation averages 996.2 Millimeters. Simonton 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. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -8.1 °C | -0.2 °C | 68.33 mm |
| February | -7 °C | 1.6 °C | 56.13 mm |
| March | -2.4 °C | 7.7 °C | 57.66 mm |
| April | 3.4 °C | 14.8 °C | 88.39 mm |
| May | 9.7 °C | 21.1 °C | 105.66 mm |
| June | 14.9 °C | 26.3 °C | 103.12 mm |
| July | 16.8 °C | 28.3 °C | 101.6 mm |
| August | 15.9 °C | 27.3 °C | 105.92 mm |
| September | 11.8 °C | 23.9 °C | 85.34 mm |
| October | 5.7 °C | 16.8 °C | 89.41 mm |
| November | 0.1 °C | 8.9 °C | 72.64 mm |
| December | -4.7 °C | 2.6 °C | 61.98 mm |
| Annual | 4.7 °C | 14.9 °C | 996.18 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 6a : -23.3°C to -20.6°C |
| Plant Hardiness Zone - 2012 | Zone 6a : -23.3°C to -20.6°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |