| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 23°F | 40°F | 31°F | 3.2" |
| February | 22°F | 41°F | 31°F | 3.2" |
| March | 29°F | 48°F | 38°F | 3.8" |
| April | 40°F | 61°F | 49°F | 3.7" |
| May | 50°F | 69°F | 58°F | 3.8" |
| June | 59°F | 78°F | 67°F | 4.7" |
| July | 66°F | 85°F | 74°F | 4.1" |
| August | 64°F | 83°F | 73°F | 3.5" |
| September | 58°F | 77°F | 66°F | 3.0" |
| October | 48°F | 66°F | 56°F | 5.0" |
| November | 37°F | 55°F | 45°F | 3.3" |
| December | 28°F | 45°F | 36°F | 4.6" |
| Index | Watertown Town | Massachusetts | National |
| Air quality index | 43 | 40 | 42 |
| Pollution index | 7,556,320 | 8,399,610 | 2,726,193 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 291 |
| Days with moderate air quality | 73 |
| Days w/ poor A.Q. for sensitive groups | 1 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.010% |
| Benzene | 0.070% |
| Carbon Tetrachloride | 0.040% |
| Lead | 0.010% |
| Mercury | 0.040% |
| City | Population | Air Quality Index | National Avg. |
| Maynard, MA | 10,900 | 40 | 20.0% |
| Littleton Common, MA | 3,370 | 40 | 20.0% |
| Framingham, MA | 72,846 | 40 | 20.0% |
| Cochituate, MA | 6,730 | 43 | 14.0% |
| Hull, MA | 10,478 | 43 | 14.0% |
| Watertown Town, MA | 35,749 | 43 | 14.0% |
| City | Population | Air Quality Index | National Avg. |
| Richmond, KY | 35,744 | 33 | 34.0% |
| Cooper City, FL | 35,715 | 41 | 18.0% |
| Foothill Farms, CA | 35,711 | 52 | 4.0% |
| El Mirage, AZ | 35,702 | 74 | 48.0% |
| Temple City, CA | 35,699 | 72 | 44.0% |
| Watertown Town, MA | 35,749 | 43 | 14.0% |
Here are the best places to live in Massachusetts
Safest States In The US
Check out the 10 most dangerous cities in Massachusetts
See the best places to live in Watertown Town