| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 19°F | 36°F | 27°F | 2.6" |
| February | 20°F | 39°F | 29°F | 2.0" |
| March | 32°F | 53°F | 42°F | 2.7" |
| April | 42°F | 66°F | 53°F | 4.3" |
| May | 51°F | 75°F | 63°F | 4.4" |
| June | 61°F | 84°F | 72°F | 5.8" |
| July | 64°F | 85°F | 74°F | 4.8" |
| August | 62°F | 85°F | 73°F | 3.6" |
| September | 55°F | 79°F | 66°F | 3.2" |
| October | 44°F | 67°F | 55°F | 3.3" |
| November | 33°F | 53°F | 43°F | 3.1" |
| December | 24°F | 40°F | 31°F | 3.1" |
| Index | Hillsboro | Indiana | National |
| Air quality index | 42 | 56 | 42 |
| Pollution index | 1,601,640 | 2,719,453 | 2,726,193 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 276 |
| Days with moderate air quality | 89 |
| Days w/ poor A.Q. for sensitive groups | 0 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.004% |
| Benzene | 0.030% |
| Carbon Tetrachloride | 0.002% |
| Lead | 0.040% |
| Mercury | 0.290% |
| City | Population | Air Quality Index | National Avg. |
| Alamo, IN | 69 | 42 | 16.0% |
| Waynetown, IN | 1,007 | 42 | 16.0% |
| Lake Holiday, IN | 1,376 | 42 | 16.0% |
| Wingate, IN | 315 | 42 | 16.0% |
| Attica, IN | 3,256 | 42 | 16.0% |
| Hillsboro, IN | 527 | 42 | 16.0% |
| City | Population | Air Quality Index | National Avg. |
| Crawfordsville, AR | 527 | 45 | 10.0% |
| Thompsonville, IL | 527 | 43 | 14.0% |
| Amo, IN | 527 | 54 | 8.0% |
| Markleville, IN | 527 | 42 | 16.0% |
| Rolla, KS | 527 | 15 | 70.0% |
| Hillsboro, IN | 527 | 42 | 16.0% |
Here are the best places to live in Indiana
See the best places to live in Hillsboro
These are the largest cities in Indiana
These are the 10 cheapest cities in Indiana