| | Poolesville, MD | Olney, MD | United States |
| Rainfall | 42 | 43 | 38 |
| Snowfall | 20 | 16 | 28 |
| Precipitation | 116 | 112 | 106 |
| Sunny | 203 | 199 | 205 |
| Avg. July High | 86 | 87 | 86 |
| Avg. Jan. Low | 25 | 25 | 22 |
| Comfort Index (higher=better) | 7.3 | 7.3 | 7 |
| UV Index | 4.1 | 4.1 | 4.3 |
| Elevation | 410 | 541 | 2443 |