Berkeley, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 41.6 °F (low) to 59.5 °F (high). Annual precipitation averages 39.3 Inches. 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 | 17.0 °F | 31.7 °F | 2.15 in. |
| February | 19.6 °F | 35.5 °F | 2.15 in. |
| March | 28.9 °F | 46.3 °F | 2.33 in. |
| April | 39.3 °F | 58.7 °F | 3.94 in. |
| May | 50.1 °F | 70.0 °F | 4.7 in. |
| June | 60.2 °F | 80.1 °F | 4.43 in. |
| July | 65.4 °F | 84.4 °F | 3.82 in. |
| August | 63.9 °F | 82.5 °F | 4.13 in. |
| September | 56.0 °F | 75.9 °F | 3.35 in. |
| October | 43.8 °F | 62.9 °F | 3.45 in. |
| November | 32.5 °F | 48.8 °F | 2.57 in. |
| December | 22.7 °F | 36.9 °F | 2.29 in. |
| Annual | 41.6 °F | 59.5 °F | 39.31 in. |
| 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 : -10°F to -5°F |
| Plant Hardiness Zone - 2012 | Zone 5b : -15°F to -10°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |