Bath, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 42 °F (low) to 63.2 °F (high). Annual precipitation averages 39.8 Inches. Bath 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 | 17.2 °F | 34.4 °F | 2.04 in. |
| February | 20.4 °F | 39.0 °F | 1.96 in. |
| March | 30.4 °F | 51.2 °F | 2.57 in. |
| April | 40.8 °F | 64.1 °F | 3.91 in. |
| May | 52.6 °F | 74.7 °F | 4.91 in. |
| June | 62.1 °F | 83.6 °F | 4.85 in. |
| July | 65.2 °F | 86.7 °F | 4.27 in. |
| August | 62.9 °F | 85.3 °F | 3.49 in. |
| September | 54.5 °F | 79.9 °F | 3.55 in. |
| October | 42.3 °F | 67.1 °F | 3.1 in. |
| November | 31.9 °F | 52.0 °F | 2.82 in. |
| December | 23.1 °F | 39.8 °F | 2.28 in. |
| Annual | 42 °F | 63.2 °F | 39.75 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 6a : -10°F to -5°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 |