Berkeley, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 5.4 °C (low) to 15.3 °C (high). Annual precipitation averages 998.5 Millimeters. Berkeley 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 | -8.3 °C | -0.2 °C | 54.61 mm |
| February | -6.9 °C | 1.9 °C | 54.61 mm |
| March | -1.7 °C | 7.9 °C | 59.18 mm |
| April | 4.1 °C | 14.8 °C | 100.08 mm |
| May | 10.1 °C | 21.1 °C | 119.38 mm |
| June | 15.7 °C | 26.7 °C | 112.52 mm |
| July | 18.6 °C | 29.1 °C | 97.03 mm |
| August | 17.7 °C | 28.1 °C | 104.9 mm |
| September | 13.3 °C | 24.4 °C | 85.09 mm |
| October | 6.6 °C | 17.2 °C | 87.63 mm |
| November | 0.3 °C | 9.3 °C | 65.28 mm |
| December | -5.2 °C | 2.7 °C | 58.17 mm |
| Annual | 5.4 °C | 15.3 °C | 998.48 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 |