| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 26°F | 41°F | 33°F | 4.1" |
| February | 25°F | 40°F | 33°F | 4.0" |
| March | 31°F | 45°F | 38°F | 3.9" |
| April | 40°F | 55°F | 47°F | 3.7" |
| May | 49°F | 64°F | 55°F | 3.8" |
| June | 57°F | 72°F | 64°F | 3.5" |
| July | 65°F | 80°F | 72°F | 3.4" |
| August | 63°F | 79°F | 71°F | 3.8" |
| September | 58°F | 73°F | 65°F | 3.5" |
| October | 49°F | 63°F | 56°F | 4.9" |
| November | 39°F | 54°F | 47°F | 4.3" |
| December | 31°F | 46°F | 39°F | 4.6" |
| Index | West Chatham | Massachusetts | National |
| Air quality index | 36 | 40 | 42 |
| Pollution index | 7,903,830 | 8,399,610 | 2,726,193 |
| Measurement | Total |
| Days measured | 359 |
| Days with good air quality | 348 |
| Days with moderate air quality | 11 |
| Days w/ poor A.Q. for sensitive groups | 0 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.060% |
| Benzene | 0.070% |
| Carbon Tetrachloride | 0.010% |
| Lead | 0.080% |
| Mercury | 0.030% |
| City | Population | Air Quality Index | National Avg. |
| Chatham, MA | 1,550 | 36 | 28.0% |
| East Dennis, MA | 3,068 | 36 | 28.0% |
| Northwest Harwich, MA | 4,123 | 36 | 28.0% |
| South Yarmouth, MA | 10,598 | 36 | 28.0% |
| Brewster, MA | 1,347 | 36 | 28.0% |
| West Chatham, MA | 1,224 | 36 | 28.0% |
| City | Population | Air Quality Index | National Avg. |
| Pioneer, CA | 1,224 | 39 | 22.0% |
| Talahi Island, GA | 1,224 | 39 | 22.0% |
| Conrad, IA | 1,224 | 39 | 22.0% |
| Arenas Valley, NM | 1,224 | 37 | 26.0% |
| Maywood Park, OR | 1,224 | 38 | 24.0% |
| West Chatham, MA | 1,224 | 36 | 28.0% |
Here are the best places to live in Massachusetts
Check out the 10 safest cities in Massachusetts
Check out the 10 most dangerous cities in Massachusetts
Safest States In The US