| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 18°F | 37°F | 27°F | 2.8" |
| February | 18°F | 39°F | 28°F | 3.3" |
| March | 26°F | 47°F | 36°F | 4.0" |
| April | 38°F | 62°F | 49°F | 3.9" |
| May | 48°F | 72°F | 59°F | 4.0" |
| June | 57°F | 80°F | 68°F | 5.0" |
| July | 63°F | 86°F | 74°F | 4.0" |
| August | 61°F | 83°F | 72°F | 3.6" |
| September | 54°F | 77°F | 65°F | 3.7" |
| October | 43°F | 65°F | 53°F | 5.8" |
| November | 32°F | 53°F | 42°F | 3.2" |
| December | 23°F | 42°F | 32°F | 4.0" |
| Index | Leominster | Massachusetts | National |
| Air quality index | 40 | 40 | 42 |
| Pollution index | 7,556,320 | 8,399,610 | 2,726,193 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 312 |
| Days with moderate air quality | 52 |
| 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. |
| Winchendon, MA | 4,673 | 34 | 32.0% |
| East Pepperell, MA | 1,916 | 37 | 26.0% |
| Groton, MA | 1,127 | 37 | 26.0% |
| Townsend, MA | 1,276 | 37 | 26.0% |
| Pepperell, MA | 2,685 | 37 | 26.0% |
| Leominster, MA | 41,581 | 40 | 20.0% |
| City | Population | Air Quality Index | National Avg. |
| Catonsville, MD | 41,592 | 46 | 8.0% |
| Woonsocket, RI | 41,616 | 44 | 12.0% |
| Charlottetown, PE | 41,537 | n/a | |
| Rancho Palos Verdes, CA | 41,635 | 72 | 44.0% |
| Mableton, GA | 41,647 | 52 | 4.0% |
| Leominster, MA | 41,581 | 40 | 20.0% |
Here are the best places to live in Massachusetts
These are the largest cities in Massachusetts
Check out the 10 most dangerous cities in Massachusetts
Most Dangerous States In The US