| | Manassas, VA | Marlow Heights, MD | United States |
| Rainfall | 42.9 | 42.7 | 38.1 |
| Snowfall | 21.5 | 14 | 27.8 |
| Precipitation Days | 119.5 | 112.7 | 106.2 |
| Sunny | 196 | 207 | 205 |
| Avg. July High | 87.6 | 88.6 | 85.8 |
| Avg. Jan. Low | 23.7 | 27.3 | 21.7 |
| Comfort Index (higher=better) | 7.3 | 7.4 | 7 |
| UV Index | 4.1 | 4.3 | 4.3 |
| Elevation ft. | 308 | 259 | 2443 |