Andalusia, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 41.6 °F (low) to 60.6 °F (high). Annual precipitation averages 37.9 Inches. Andalusia is located in USDA Plant Hardiness Zone 5b. 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 | 15.0 °F | 31.0 °F | 1.48 in. |
| February | 18.5 °F | 35.4 °F | 1.75 in. |
| March | 29.2 °F | 48.3 °F | 2.47 in. |
| April | 40.4 °F | 61.6 °F | 3.71 in. |
| May | 52.2 °F | 72.7 °F | 4.87 in. |
| June | 62.2 °F | 82.1 °F | 4.88 in. |
| July | 65.9 °F | 85.2 °F | 4.16 in. |
| August | 63.6 °F | 83.3 °F | 3.98 in. |
| September | 55.4 °F | 77.3 °F | 3.56 in. |
| October | 43.6 °F | 64.5 °F | 2.86 in. |
| November | 31.5 °F | 49.3 °F | 2.27 in. |
| December | 21.1 °F | 36.3 °F | 1.95 in. |
| Annual | 41.6 °F | 60.6 °F | 37.94 in. |
| 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 5b : -15°F to -10°F |
| Plant Hardiness Zone - 2012 | Zone 5b : -15°F to -10°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |