| | Chatham, IL | Madison, IL | United States |
| Rainfall | 38.1 | 42.2 | 38.1 |
| Snowfall | 18.5 | 14.9 | 27.8 |
| Precipitation Days | 101.2 | 103.5 | 106.2 |
| Sunny | 201 | 202 | 205 |
| Avg. July High | 85.8 | 88.5 | 85.8 |
| Avg. Jan. Low | 18.2 | 22.6 | 21.7 |
| Comfort Index (higher=better) | 7.2 | 7.2 | 7 |
| UV Index | 3.9 | 4.1 | 4.3 |
| Elevation ft. | 604 | 413 | 2443 |