Germantown Hills, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 4.9 °C (low) to 16.1 °C (high). Annual precipitation averages 976.9 Millimeters. Germantown Hills is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -9.2 °C | -0.1 °C | 54.36 mm |
| February | -7.3 °C | 2.6 °C | 52.07 mm |
| March | -1.9 °C | 9.4 °C | 65.02 mm |
| April | 4.2 °C | 16.7 °C | 97.28 mm |
| May | 10.7 °C | 22.7 °C | 119.13 mm |
| June | 16.1 °C | 27.7 °C | 113.54 mm |
| July | 17.9 °C | 29.4 °C | 96.27 mm |
| August | 16.7 °C | 28.5 °C | 89.41 mm |
| September | 12.3 °C | 25.5 °C | 88.9 mm |
| October | 5.8 °C | 18.3 °C | 79.25 mm |
| November | -0.6 °C | 9.9 °C | 68.58 mm |
| December | -6 °C | 2.9 °C | 53.09 mm |
| Annual | 4.9 °C | 16.1 °C | 976.9 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 100-125 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 | Dfa - Humid Continental Hot Summers With Year Around Precipitation |