Red Bud, Illinois has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 7.9 °C (low) to 19.3 °C (high). Annual precipitation averages 1103.9 Millimeters. Red Bud is located in USDA Plant Hardiness Zone 7a. The growing season typically runs from the last frost around Apr. 1 - Apr. 10 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -4.8 °C | 4.8 °C | 68.58 mm |
| February | -2.9 °C | 7.7 °C | 63.25 mm |
| March | 1.7 °C | 13.3 °C | 91.69 mm |
| April | 7.4 °C | 19.9 °C | 124.46 mm |
| May | 13.4 °C | 24.9 °C | 130.56 mm |
| June | 18.3 °C | 29.8 °C | 113.03 mm |
| July | 20.4 °C | 31.6 °C | 99.82 mm |
| August | 19.3 °C | 31 °C | 79.25 mm |
| September | 14.5 °C | 27.4 °C | 82.3 mm |
| October | 8.1 °C | 21.1 °C | 77.22 mm |
| November | 2.2 °C | 13.2 °C | 97.28 mm |
| December | -2.6 °C | 7 °C | 76.45 mm |
| Annual | 7.9 °C | 19.3 °C | 1103.89 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| Average Days With Frost | 75-100 Days |
| Plant Hardiness Zone | Zone 7a : -17.8°C to -15°C |
| Plant Hardiness Zone - 2012 | Zone 6b : -20.6°C to -17.8°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |