| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | -2°F | 69°F | 31°F | 3.4" |
| February | 7°F | 63°F | 31°F | 2.9" |
| March | 5°F | 73°F | 37°F | 3.0" |
| April | 28°F | 93°F | 49°F | 4.0" |
| May | 39°F | 92°F | 57°F | 5.3" |
| June | 48°F | 97°F | 67°F | 4.4" |
| July | 55°F | 97°F | 73°F | 5.1" |
| August | 55°F | 99°F | 72°F | 2.8" |
| September | 45°F | 95°F | 66°F | 3.0" |
| October | 33°F | 86°F | 55°F | 4.6" |
| November | 21°F | 70°F | 46°F | 3.8" |
| December | 10°F | 70°F | 35°F | 4.0" |
| Index | Boston | Massachusetts | National |
| Air quality index | 47 | 40 | 50 |
| Pollution index | 24,018,000 | 12,377,839 | 5,066,862 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 223 |
| Days with moderate air quality | 137 |
| Days w/ poor A.Q. for sensitive groups | 5 |
| Days with unhealthy air quality |
| Pollutant | Total |
| Arsenic | 0.030% |
| Benzene | 0.220% |
| Carbon Tetrachloride | 0.100% |
| Lead | 0.280% |
| Mercury | 0.130% |
| City, State | Population | Air Quality Index | National Avg. |
| Belmont, MA | 25,555 | 47 | 6% |
| Burlington, MA | 25,698 | 47 | 6% |
| Danvers, MA | 27,558 | 47 | 6% |
| Hanscom AFB, MA | 1,943 | 47 | 6% |
| Lynn, MA | 92,074 | 47 | 6% |
| Boston, MA | 658,279 | 47 | 6% |
| City, State | Population | Air Quality Index | National Avg. |
| Washington, DC | 659,009 | 49 | 2% |
| Memphis, TN | 655,857 | 44 | 12% |
| Denver, CO | 663,303 | 54 | 8% |
| Seattle, WA | 668,849 | 49 | 2% |
| Nashville, TN | 643,771 | 45 | 10% |
| Boston, MA | 658,279 | 47 | 6% |