| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 9°F | 25°F | 17°F | 1.9" |
| February | 11°F | 29°F | 19°F | 1.9" |
| March | 26°F | 43°F | 34°F | 3.2" |
| April | 37°F | 59°F | 47°F | 3.3" |
| May | 48°F | 71°F | 59°F | 5.1" |
| June | 59°F | 79°F | 69°F | 7.0" |
| July | 62°F | 83°F | 72°F | 7.4" |
| August | 59°F | 80°F | 69°F | 5.1" |
| September | 53°F | 74°F | 62°F | 8.7" |
| October | 40°F | 60°F | 49°F | 3.9" |
| November | 28°F | 46°F | 36°F | 4.9" |
| December | 14°F | 29°F | 22°F | 2.9" |
| Index | Farmington | Minnesota | National |
| Air quality index | 46 | 35 | 42 |
| Pollution index | 7,686,740 | 1,854,519 | 2,726,193 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 214 |
| Days with moderate air quality | 148 |
| Days w/ poor A.Q. for sensitive groups | 2 |
| Days with unhealthy air quality | 1 |
| Pollutant | Total |
| Arsenic | 0.070% |
| Benzene | 0.100% |
| Carbon Tetrachloride | 0.010% |
| Lead | 0.350% |
| Mercury | 0.120% |
| City | Population | Air Quality Index | National Avg. |
| Cannon Falls, MN | 4,154 | 37 | 26.0% |
| Vermillion, MN | 494 | 37 | 26.0% |
| Hampton, MN | 610 | 37 | 26.0% |
| Northfield, MN | 21,004 | 37 | 26.0% |
| Randolph, MN | 494 | 37 | 26.0% |
| Farmington, MN | 23,819 | 46 | 8.0% |
| City | Population | Air Quality Index | National Avg. |
| Rock Springs, WY | 23,823 | 46 | 8.0% |
| Oakdale, CA | 23,805 | 49 | 2.0% |
| Auburn, ME | 23,804 | 31 | 38.0% |
| Fort Hood, TX | 23,849 | 42 | 16.0% |
| Oxford, OH | 23,787 | 6 | 88.0% |
| Farmington, MN | 23,819 | 46 | 8.0% |