Glencoe, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 6.2 °C (low) to 14.7 °C (high). Annual precipitation averages 977.9 Millimeters. Glencoe 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. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -7.4 °C | -0.1 °C | 52.83 mm |
| February | -5.8 °C | 1.9 °C | 50.55 mm |
| March | -1.1 °C | 7.2 °C | 55.63 mm |
| April | 4.4 °C | 13.6 °C | 96.01 mm |
| May | 10.1 °C | 20.1 °C | 118.11 mm |
| June | 15.7 °C | 25.6 °C | 108.2 mm |
| July | 19.4 °C | 28.2 °C | 93.47 mm |
| August | 19.1 °C | 27.3 °C | 103.89 mm |
| September | 14.9 °C | 23.6 °C | 85.85 mm |
| October | 8.1 °C | 17.1 °C | 88.9 mm |
| November | 1.6 °C | 9.1 °C | 66.8 mm |
| December | -4.1 °C | 2.8 °C | 57.66 mm |
| Annual | 6.2 °C | 14.7 °C | 977.9 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| 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 |