| | Westford, MA | Littleton, MA | United States |
| Rainfall | 48.4 | 48.5 | 38.1 |
| Snowfall | 56.1 | 56.1 | 27.8 |
| Precipitation Days | 128.2 | 128.4 | 106.2 |
| Sunny | 199 | 199 | 205 |
| Avg. July High | 83.4 | 83.4 | 85.8 |
| Avg. Jan. Low | 15 | 15 | 21.7 |
| Comfort Index (higher=better) | 6.8 | 6.8 | 7 |
| UV Index | 3.5 | 3.5 | 4.3 |
| Elevation ft. | 397 | 226 | 2443 |