| | Millsboro, DE | Herndon, VA | United States |
| Rainfall | 45.8 | 42.9 | 38.1 |
| Snowfall | 10.8 | 21.5 | 27.8 |
| Precipitation Days | 123 | 119.5 | 106.2 |
| Sunny | 200 | 201 | 205 |
| Avg. July High | 86.8 | 85.8 | 85.8 |
| Avg. Jan. Low | 27.2 | 23.5 | 21.7 |
| Comfort Index (higher=better) | 7.4 | 7.3 | 7 |
| UV Index | 3.9 | 4 | 4.3 |
| Elevation ft. | 23 | 361 | 2443 |