| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 8°F | 26°F | 17°F | 1.7" |
| February | 10°F | 28°F | 18°F | 1.0" |
| March | 24°F | 43°F | 32°F | 2.8" |
| April | 36°F | 58°F | 46°F | 3.4" |
| May | 48°F | 71°F | 58°F | 5.6" |
| June | 58°F | 80°F | 68°F | 6.7" |
| July | 63°F | 84°F | 73°F | 5.9" |
| August | 60°F | 81°F | 69°F | 7.6" |
| September | 52°F | 75°F | 62°F | 6.8" |
| October | 40°F | 60°F | 49°F | 5.7" |
| November | 27°F | 46°F | 35°F | 2.3" |
| December | 12°F | 28°F | 19°F | 2.2" |
| Index | Marshall | Minnesota | National |
| Air quality index | 32 | 35 | 42 |
| Pollution index | 1,069,770 | 1,854,519 | 2,726,193 |
| Measurement | Total |
| Days measured | 362 |
| Days with good air quality | 327 |
| Days with moderate air quality | 35 |
| Days w/ poor A.Q. for sensitive groups | 0 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.003% |
| Benzene | 0.040% |
| Carbon Tetrachloride | 0.001% |
| Lead | 0.020% |
| Mercury | 0.003% |
| City | Population | Air Quality Index | National Avg. |
| Lynd, MN | 432 | 32 | 36.0% |
| Wood Lake, MN | 395 | 32 | 36.0% |
| Florence, MN | 24 | 32 | 36.0% |
| Minneota, MN | 1,350 | 32 | 36.0% |
| Cottonwood, MN | 1,223 | 32 | 36.0% |
| Marshall, MN | 14,075 | 32 | 36.0% |
| City | Population | Air Quality Index | National Avg. |
| St. Helens, OR | 14,078 | 18 | 64.0% |
| Lockhart, TX | 14,070 | 44 | 12.0% |
| Forest City, FL | 14,081 | 39 | 22.0% |
| Andrews, TX | 14,081 | 28 | 44.0% |
| Royse City, TX | 14,081 | 51 | 2.0% |
| Marshall, MN | 14,075 | 32 | 36.0% |