| | Harpers Ferry, WV | Columbia, MD | United States |
| Rainfall | 40.3 | 45 | 38.1 |
| Snowfall | 19.8 | 17.3 | 27.8 |
| Precipitation Days | 114.8 | 113.9 | 106.2 |
| Sunny | 201 | 212 | 205 |
| Avg. July High | 86.1 | 87.9 | 85.8 |
| Avg. Jan. Low | 21.3 | 23.9 | 21.7 |
| Comfort Index (higher=better) | 7.3 | 7.3 | 7 |
| UV Index | 3.9 | 3.9 | 4.3 |
| Elevation ft. | 489 | 404 | 2443 |