| | Potomac, MD | Wolf Trap, VA | United States |
| Rainfall | 42 | 42.5 | 38.1 |
| Snowfall | 16.8 | 21.4 | 27.8 |
| Precipitation Days | 114 | 116.5 | 106.2 |
| Sunny | 201 | 202 | 205 |
| Avg. July High | 85.7 | 85.5 | 85.8 |
| Avg. Jan. Low | 25.3 | 23.5 | 21.7 |
| Comfort Index (higher=better) | 7.3 | 7.3 | 7 |
| UV Index | 4.1 | 4 | 4.3 |
| Elevation ft. | 361 | 279 | 2443 |