Buffalo, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 5.9 °C (low) to 17.3 °C (high). Annual precipitation averages 974.8 Millimeters. Buffalo 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. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -7.4 °C | 1.7 °C | 53.09 mm |
| February | -5.8 °C | 4.4 °C | 49.53 mm |
| March | -0.7 °C | 10.8 °C | 67.56 mm |
| April | 5.4 °C | 17.9 °C | 101.85 mm |
| May | 11.8 °C | 23.6 °C | 115.82 mm |
| June | 16.8 °C | 28.3 °C | 116.59 mm |
| July | 18.4 °C | 29.9 °C | 95.76 mm |
| August | 17.4 °C | 29.2 °C | 84.07 mm |
| September | 12.7 °C | 26.3 °C | 78.74 mm |
| October | 6.2 °C | 19.4 °C | 82.04 mm |
| November | 0.3 °C | 11.1 °C | 74.93 mm |
| December | -4.4 °C | 4.5 °C | 54.86 mm |
| Annual | 5.9 °C | 17.3 °C | 974.84 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| 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 |