Gorham, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 8.1 °C (low) to 19.7 °C (high). Annual precipitation averages 1168.4 Millimeters. Gorham is located in USDA Plant Hardiness Zone 7a. The growing season typically runs from the last frost around Apr. 1 - Apr. 10 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -4.4 °C | 5.3 °C | 75.95 mm |
| February | -2.2 °C | 8.1 °C | 76.45 mm |
| March | 2 °C | 13.8 °C | 108.2 mm |
| April | 7.8 °C | 20 °C | 133.35 mm |
| May | 13.5 °C | 25.1 °C | 131.83 mm |
| June | 18.6 °C | 30 °C | 116.08 mm |
| July | 20.5 °C | 31.7 °C | 92.71 mm |
| August | 19.1 °C | 31 °C | 76.2 mm |
| September | 14.3 °C | 28 °C | 76.45 mm |
| October | 7.7 °C | 21.7 °C | 88.14 mm |
| November | 2.4 °C | 13.8 °C | 107.19 mm |
| December | -2.2 °C | 7.4 °C | 85.85 mm |
| Annual | 8.1 °C | 19.7 °C | 1168.4 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| Average Days With Frost | 75-100 Days |
| Plant Hardiness Zone | Zone 7a : -17.8°C to -15°C |
| Plant Hardiness Zone - 2012 | Zone 6b : -20.6°C to -17.8°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |