Elgin, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 4.2 °C (low) to 15.1 °C (high). Annual precipitation averages 1001.5 Millimeters. Elgin is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -9.6 °C | -0.7 °C | 49.53 mm |
| February | -8.1 °C | 1.4 °C | 46.74 mm |
| March | -2.8 °C | 7.9 °C | 58.17 mm |
| April | 2.9 °C | 14.9 °C | 97.28 mm |
| May | 9.1 °C | 21.3 °C | 131.32 mm |
| June | 14.7 °C | 26.8 °C | 118.11 mm |
| July | 17.3 °C | 29.1 °C | 99.82 mm |
| August | 16.3 °C | 27.9 °C | 105.16 mm |
| September | 11.9 °C | 24.4 °C | 90.17 mm |
| October | 5.4 °C | 17.1 °C | 85.09 mm |
| November | -0.8 °C | 8.9 °C | 65.02 mm |
| December | -6.3 °C | 2.2 °C | 55.12 mm |
| Annual | 4.2 °C | 15.1 °C | 1001.53 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 5b : -26.1°C to -23.3°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 |