| | Grinnell, IA | Tiffin, IA | United States |
| Rainfall | 36.6 | 36.9 | 38.1 |
| Snowfall | 27.2 | 26.8 | 27.8 |
| Precipitation Days | 103.8 | 97.1 | 106.2 |
| Sunny | 196 | 193 | 205 |
| Avg. July High | 83.9 | 85.1 | 85.8 |
| Avg. Jan. Low | 9.8 | 13.1 | 21.7 |
| Comfort Index (higher=better) | 6.8 | 7 | 7 |
| UV Index | 3.7 | 4 | 4.3 |
| Elevation ft. | 1014 | 712 | 2443 |