Burnham, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 6.2 °C (low) to 15.3 °C (high). Annual precipitation averages 1007.9 Millimeters. Burnham 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 | -7.3 °C | 0.4 °C | 57.66 mm |
| February | -5.8 °C | 2.4 °C | 53.34 mm |
| March | -0.9 °C | 8 °C | 60.2 mm |
| April | 4.7 °C | 14.8 °C | 92.96 mm |
| May | 10.6 °C | 20.8 °C | 107.7 mm |
| June | 16.1 °C | 26.3 °C | 115.57 mm |
| July | 19.2 °C | 28.4 °C | 110.49 mm |
| August | 18.4 °C | 27.7 °C | 104.65 mm |
| September | 14.1 °C | 24.4 °C | 82.8 mm |
| October | 7.6 °C | 17.4 °C | 92.2 mm |
| November | 1.4 °C | 9.8 °C | 71.12 mm |
| December | -4.2 °C | 3.3 °C | 59.18 mm |
| Annual | 6.2 °C | 15.3 °C | 1007.87 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 6a : -23.3°C to -20.6°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |