| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 8°F | 28°F | 18°F | 1.0" |
| February | 9°F | 30°F | 20°F | 0.6" |
| March | 24°F | 46°F | 34°F | 1.5" |
| April | 34°F | 59°F | 46°F | 3.7" |
| May | 44°F | 71°F | 57°F | 4.5" |
| June | 54°F | 80°F | 67°F | 5.6" |
| July | 57°F | 84°F | 71°F | 6.2" |
| August | 56°F | 81°F | 68°F | 4.8" |
| September | 48°F | 74°F | 60°F | 5.4" |
| October | 37°F | 61°F | 48°F | 3.4" |
| November | 27°F | 46°F | 36°F | 1.5" |
| December | 14°F | 32°F | 23°F | 2.3" |
| Index | Tunnel City | Wisconsin | National |
| Air quality index | 35 | 69 | 42 |
| Pollution index | 1,453,040 | 2,842,418 | 2,726,193 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 310 |
| Days with moderate air quality | 55 |
| 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 | 0.000% |
| Lead | 0.000% |
| Mercury | 0.000% |
| City | Population | Air Quality Index | National Avg. |
| Norwalk, WI | 713 | 35 | 30.0% |
| Oakdale, WI | 266 | 35 | 30.0% |
| Wyeville, WI | 158 | 35 | 30.0% |
| Cataract, WI | 166 | 35 | 30.0% |
| Sparta, WI | 9,751 | 35 | 30.0% |
| Tunnel City, WI | 124 | 35 | 30.0% |
| City | Population | Air Quality Index | National Avg. |
| Hyampom, CA | 124 | 27 | 46.0% |
| Nicolaus, CA | 124 | 44 | 12.0% |
| Weott, CA | 124 | 27 | 46.0% |
| Osterdock, IA | 124 | 29 | 42.0% |
| Elk River, ID | 124 | 10 | 80.0% |
| Tunnel City, WI | 124 | 35 | 30.0% |
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