Addison, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 5 °C (low) to 15.2 °C (high). Annual precipitation averages 989.8 Millimeters. Addison is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -8.7 °C | -0.3 °C | 53.85 mm |
| February | -7.2 °C | 1.8 °C | 53.34 mm |
| March | -2 °C | 8 °C | 57.91 mm |
| April | 3.7 °C | 14.8 °C | 97.28 mm |
| May | 9.7 °C | 21.1 °C | 120.9 mm |
| June | 15.3 °C | 26.7 °C | 114.55 mm |
| July | 18.2 °C | 29.1 °C | 92.96 mm |
| August | 17.4 °C | 27.9 °C | 104.9 mm |
| September | 12.9 °C | 24.2 °C | 85.34 mm |
| October | 6.2 °C | 17.1 °C | 86.36 mm |
| November | -0.1 °C | 9.2 °C | 65.28 mm |
| December | -5.4 °C | 2.6 °C | 57.15 mm |
| Annual | 5 °C | 15.2 °C | 989.82 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| 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 | Abnormally Dry |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |