| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 6°F | 23°F | 14°F | 1.2" |
| February | 8°F | 27°F | 17°F | 1.0" |
| March | 22°F | 42°F | 31°F | 2.4" |
| April | 34°F | 56°F | 44°F | 3.9" |
| May | 45°F | 69°F | 56°F | 7.5" |
| June | 54°F | 77°F | 65°F | 5.5" |
| July | 59°F | 82°F | 70°F | 6.6" |
| August | 57°F | 79°F | 67°F | 8.4" |
| September | 50°F | 72°F | 60°F | 5.7" |
| October | 38°F | 57°F | 47°F | 6.0" |
| November | 26°F | 43°F | 34°F | 2.3" |
| December | 12°F | 26°F | 19°F | 1.8" |
| Index | North Branch | Minnesota | National |
| Air quality index | 46 | 35 | 42 |
| Pollution index | 1,318,690 | 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 | 0.001% |
| Benzene | 0.020% |
| Carbon Tetrachloride | 0.000% |
| Lead | 0.000% |
| Mercury | 0.004% |
| City | Population | Air Quality Index | National Avg. |
| Braham, MN | 1,774 | 32 | 36.0% |
| Stanchfield, MN | 74 | 46 | 8.0% |
| East Bethel, MN | 12,391 | 46 | 8.0% |
| Chisago City, MN | 5,337 | 46 | 8.0% |
| Shafer, MN | 1,181 | 46 | 8.0% |
| North Branch, MN | 10,855 | 46 | 8.0% |
| City | Population | Air Quality Index | National Avg. |
| Shelton, WA | 10,858 | 21 | 58.0% |
| Petal, MS | 10,849 | 35 | 30.0% |
| Martin, TN | 10,847 | 26 | 48.0% |
| Atchison, KS | 10,863 | 43 | 14.0% |
| South Yarmouth, MA | 10,841 | 36 | 28.0% |
| North Branch, MN | 10,855 | 46 | 8.0% |