Godfrey, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 7.9 °C (low) to 18.4 °C (high). Annual precipitation averages 1078.7 Millimeters. Godfrey 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 Nov. 1 - Nov. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -5.3 °C | 3.6 °C | 65.02 mm |
| February | -3.6 °C | 6.6 °C | 57.91 mm |
| March | 1.6 °C | 12.4 °C | 83.57 mm |
| April | 7.4 °C | 18.9 °C | 119.63 mm |
| May | 13.6 °C | 24.1 °C | 129.54 mm |
| June | 18.6 °C | 28.9 °C | 109.73 mm |
| July | 20.4 °C | 30.4 °C | 98.81 mm |
| August | 19.4 °C | 30.2 °C | 92.96 mm |
| September | 14.7 °C | 26.6 °C | 83.57 mm |
| October | 8.3 °C | 20.2 °C | 82.8 mm |
| November | 2.1 °C | 12.3 °C | 88.14 mm |
| December | -2.7 °C | 6.2 °C | 67.06 mm |
| Annual | 7.9 °C | 18.4 °C | 1078.74 mm |
| Average First Frost Date | Nov. 1 - Nov. 10 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| Average Days With Frost | 75-100 Days |
| Plant Hardiness Zone | Zone 6b : -20.6°C to -17.8°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 |