East Gillespie, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 6.7 °C (low) to 17.6 °C (high). Annual precipitation averages 1063 Millimeters. East Gillespie 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. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -6.4 °C | 2.3 °C | 63.75 mm |
| February | -4.6 °C | 5.2 °C | 56.13 mm |
| March | 0.4 °C | 11.3 °C | 78.49 mm |
| April | 6.2 °C | 18.1 °C | 120.4 mm |
| May | 12.4 °C | 23.5 °C | 126.49 mm |
| June | 17.4 °C | 28.3 °C | 109.98 mm |
| July | 19.1 °C | 30 °C | 100.08 mm |
| August | 17.9 °C | 29.5 °C | 87.38 mm |
| September | 13.2 °C | 26.4 °C | 84.58 mm |
| October | 6.9 °C | 19.7 °C | 82.55 mm |
| November | 1.3 °C | 11.5 °C | 88.14 mm |
| December | -3.7 °C | 5 °C | 65.02 mm |
| Annual | 6.7 °C | 17.6 °C | 1062.99 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 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 |