| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 12°F | 29°F | 20°F | 2.3" |
| February | 10°F | 30°F | 20°F | 1.4" |
| March | 19°F | 42°F | 30°F | 2.1" |
| April | 30°F | 57°F | 43°F | 3.5" |
| May | 42°F | 70°F | 56°F | 3.2" |
| June | 51°F | 79°F | 65°F | 3.9" |
| July | 55°F | 82°F | 69°F | 2.9" |
| August | 53°F | 80°F | 67°F | 3.0" |
| September | 46°F | 73°F | 59°F | 2.8" |
| October | 37°F | 60°F | 48°F | 3.1" |
| November | 28°F | 46°F | 37°F | 2.2" |
| December | 18°F | 33°F | 26°F | 2.2" |
| Index | Harrison | Michigan | National |
| Air quality index | 36 | 69 | 42 |
| Pollution index | 1,927,350 | 4,161,606 | 2,726,193 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 330 |
| Days with moderate air quality | 35 |
| Days w/ poor A.Q. for sensitive groups | 0 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.002% |
| Benzene | 0.020% |
| Carbon Tetrachloride | 0.002% |
| Lead | 0.010% |
| Mercury | 0.000% |
| City | Population | Air Quality Index | National Avg. |
| Farwell, MI | 987 | 36 | 28.0% |
| Clare, MI | 3,234 | 36 | 28.0% |
| Harrison, MI | 2,083 | 36 | 28.0% |
| City | Population | Air Quality Index | National Avg. |
| Hoschton, GA | 2,083 | 37 | 26.0% |
| Mountain Lake, MN | 2,083 | 32 | 36.0% |
| Upton, QC | 2,083 | n/a | |
| Steep Falls, ME | 2,082 | 40 | 20.0% |
| Winsted, MN | 2,084 | 46 | 8.0% |
| Harrison, MI | 2,083 | 36 | 28.0% |