| | Gaithersburg, MD | Gettysburg, PA | United States |
| Rainfall | 42.2 | 42.9 | 38.1 |
| Snowfall | 21.4 | 25.1 | 27.8 |
| Precipitation Days | 112.7 | 119.1 | 106.2 |
| Sunny | 202 | 195 | 205 |
| Avg. July High | 85.1 | 85.5 | 85.8 |
| Avg. Jan. Low | 25 | 20.6 | 21.7 |
| Comfort Index (higher=better) | 7.3 | 7.2 | 7 |
| UV Index | 4.1 | 4.2 | 4.3 |
| Elevation ft. | 502 | 535 | 2443 |