| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 6°F | 24°F | 14°F | 1.1" |
| February | 7°F | 27°F | 16°F | 2.1" |
| March | 20°F | 39°F | 29°F | 3.6" |
| April | 31°F | 49°F | 39°F | 3.9" |
| May | 38°F | 61°F | 48°F | 5.1" |
| June | 47°F | 71°F | 58°F | 6.2" |
| July | 55°F | 80°F | 67°F | 5.7" |
| August | 54°F | 77°F | 65°F | 8.3" |
| September | 47°F | 69°F | 57°F | 5.6" |
| October | 36°F | 56°F | 45°F | 6.2" |
| November | 25°F | 42°F | 33°F | 2.4" |
| December | 11°F | 26°F | 19°F | 3.0" |
| Index | Barnum | Minnesota | National |
| Air quality index | 35 | 35 | 42 |
| Pollution index | 521,015 | 1,854,519 | 2,726,193 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 326 |
| Days with moderate air quality | 38 |
| Days w/ poor A.Q. for sensitive groups | 1 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.001% |
| Benzene | 0.020% |
| Carbon Tetrachloride | 0.000% |
| Lead | 0.003% |
| Mercury | 0.000% |
| City | Population | Air Quality Index | National Avg. |
| Cromwell, MN | 359 | 35 | 30.0% |
| Mahtowa, MN | 373 | 35 | 30.0% |
| Carlton, MN | 1,006 | 35 | 30.0% |
| Denham, MN | 32 | 35 | 30.0% |
| Moose Lake, MN | 2,804 | 35 | 30.0% |
| Barnum, MN | 618 | 35 | 30.0% |
| City | Population | Air Quality Index | National Avg. |
| Louisville, AL | 618 | 35 | 30.0% |
| McDowell, KY | 618 | 45 | 10.0% |
| Green Acres, ND | 618 | 36 | 28.0% |
| Cañada de los Alamos, NM | 618 | 44 | 12.0% |
| Tryon, OK | 618 | 36 | 28.0% |
| Barnum, MN | 618 | 35 | 30.0% |
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