Germantown, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 45.8 °F (low) to 65.9 °F (high). Annual precipitation averages 41.9 Inches. Germantown is located in USDA Plant Hardiness Zone 6b. The growing season typically runs from the last frost around Apr. 1 - Apr. 10 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 22.3 °F | 39.4 °F | 2.7 in. |
| February | 25.5 °F | 44.5 °F | 2.28 in. |
| March | 34.8 °F | 55.0 °F | 3.23 in. |
| April | 45.3 °F | 67.0 °F | 4.64 in. |
| May | 56.1 °F | 76.1 °F | 4.79 in. |
| June | 64.9 °F | 85.0 °F | 4.7 in. |
| July | 68.3 °F | 88.3 °F | 3.85 in. |
| August | 66.1 °F | 87.4 °F | 3.09 in. |
| September | 57.6 °F | 80.5 °F | 3.2 in. |
| October | 46.1 °F | 68.9 °F | 3.04 in. |
| November | 35.5 °F | 55.0 °F | 3.62 in. |
| December | 26.8 °F | 43.8 °F | 2.72 in. |
| Annual | 45.8 °F | 65.9 °F | 41.86 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| Average Days With Frost | 75-100 Days |
| Plant Hardiness Zone | Zone 6b : -5°F to 0°F |
| Plant Hardiness Zone - 2012 | Zone 6b : -5°F to 0°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |