| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 7°F | 25°F | 16°F | 0.9" |
| February | 9°F | 28°F | 19°F | 1.1" |
| March | 23°F | 43°F | 33°F | 1.9" |
| April | 35°F | 60°F | 47°F | 3.7" |
| May | 46°F | 71°F | 58°F | 4.4" |
| June | 57°F | 81°F | 68°F | 5.8" |
| July | 60°F | 83°F | 72°F | 3.7" |
| August | 58°F | 80°F | 69°F | 5.0" |
| September | 50°F | 76°F | 62°F | 4.6" |
| October | 39°F | 62°F | 49°F | 2.8" |
| November | 26°F | 47°F | 36°F | 1.5" |
| December | 12°F | 29°F | 21°F | 2.2" |
| Index | Stewartville | Minnesota | National |
| Air quality index | 36 | 35 | 42 |
| Pollution index | 904,857 | 1,854,519 | 2,726,193 |
| Measurement | Total |
| Days measured | 364 |
| Days with good air quality | 313 |
| Days with moderate air quality | 51 |
| Days w/ poor A.Q. for sensitive groups | 0 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.001% |
| Benzene | 0.030% |
| Carbon Tetrachloride | 0.001% |
| Lead | 0.002% |
| Mercury | 0.000% |
| City | Population | Air Quality Index | National Avg. |
| Spring Valley, MN | 2,395 | 36 | 28.0% |
| Grand Meadow, MN | 1,095 | 36 | 28.0% |
| Wykoff, MN | 417 | 36 | 28.0% |
| Byron, MN | 5,536 | 36 | 28.0% |
| Kasson, MN | 6,425 | 36 | 28.0% |
| Stewartville, MN | 6,123 | 36 | 28.0% |
| City | Population | Air Quality Index | National Avg. |
| Sheridan, OR | 6,122 | 32 | 36.0% |
| Piedmont, SC | 6,122 | 46 | 8.0% |
| Los Ranchos de Albuquerque, NM | 6,120 | 53 | 6.0% |
| Foxborough, MA | 6,119 | 44 | 12.0% |
| Pauls Valley, OK | 6,128 | 43 | 14.0% |
| Stewartville, MN | 6,123 | 36 | 28.0% |
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