Kaskaskia, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 7.7 °C (low) to 19.6 °C (high). Annual precipitation averages 1102.9 Millimeters. Kaskaskia is located in USDA Plant Hardiness Zone 7a. 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 | -4.7 °C | 5.2 °C | 68.58 mm |
| February | -2.6 °C | 8.3 °C | 65.53 mm |
| March | 1.6 °C | 13.7 °C | 90.42 mm |
| April | 7.2 °C | 20.1 °C | 123.44 mm |
| May | 13.2 °C | 25.2 °C | 134.62 mm |
| June | 18.2 °C | 30 °C | 107.7 mm |
| July | 20.1 °C | 31.6 °C | 100.33 mm |
| August | 18.8 °C | 31.5 °C | 78.23 mm |
| September | 13.9 °C | 27.6 °C | 79.76 mm |
| October | 7.4 °C | 21.4 °C | 81.28 mm |
| November | 1.9 °C | 13.6 °C | 95.5 mm |
| December | -2.8 °C | 7.2 °C | 77.47 mm |
| Annual | 7.7 °C | 19.6 °C | 1102.86 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 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 | Dfa - Humid Continental Hot Summers With Year Around Precipitation |