| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 14°F | 34°F | 24°F | 2.7" |
| February | 14°F | 36°F | 25°F | 2.8" |
| March | 23°F | 45°F | 33°F | 3.3" |
| April | 34°F | 60°F | 47°F | 3.5" |
| May | 45°F | 71°F | 57°F | 3.4" |
| June | 54°F | 78°F | 66°F | 5.5" |
| July | 60°F | 84°F | 71°F | 4.1" |
| August | 57°F | 81°F | 69°F | 4.3" |
| September | 50°F | 75°F | 62°F | 4.1" |
| October | 40°F | 62°F | 50°F | 6.2" |
| November | 29°F | 50°F | 39°F | 3.0" |
| December | 21°F | 40°F | 30°F | 4.2" |
| Index | Northfield | Massachusetts | National |
| Air quality index | 34 | 40 | 42 |
| Pollution index | 6,602,810 | 8,399,610 | 2,726,193 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 348 |
| Days with moderate air quality | 17 |
| Days w/ poor A.Q. for sensitive groups | 0 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.010% |
| Benzene | 0.070% |
| Carbon Tetrachloride | 0.020% |
| Lead | 0.060% |
| Mercury | 0.010% |
| City | Population | Air Quality Index | National Avg. |
| Athol, MA | 8,568 | 34 | 32.0% |
| Orange, MA | 3,966 | 34 | 32.0% |
| Troy, NH | 879 | 34 | 32.0% |
| West Brattleboro, VT | 3,108 | 34 | 32.0% |
| Turners Falls, MA | 3,779 | 34 | 32.0% |
| Northfield, MA | 999 | 34 | 32.0% |
| City | Population | Air Quality Index | National Avg. |
| Minkler, CA | 999 | 60 | 20.0% |
| Bow Mar, CO | 999 | 58 | 16.0% |
| Arnolds Park, IA | 999 | 36 | 28.0% |
| North Branch, MI | 999 | 38 | 24.0% |
| Lake Tapawingo, MO | 999 | 47 | 6.0% |
| Northfield, MA | 999 | 34 | 32.0% |