| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 20°F | 36°F | 28°F | 2.4" |
| February | 21°F | 38°F | 29°F | 2.3" |
| March | 33°F | 52°F | 42°F | 4.0" |
| April | 42°F | 65°F | 53°F | 4.6" |
| May | 53°F | 75°F | 64°F | 4.6" |
| June | 62°F | 83°F | 72°F | 5.5" |
| July | 64°F | 85°F | 74°F | 3.2" |
| August | 61°F | 83°F | 72°F | 3.8" |
| September | 55°F | 78°F | 66°F | 3.0" |
| October | 44°F | 66°F | 55°F | 3.4" |
| November | 34°F | 53°F | 43°F | 3.4" |
| December | 26°F | 41°F | 33°F | 3.6" |
| Index | Middletown | Indiana | National |
| Air quality index | 42 | 56 | 42 |
| Pollution index | 1,974,040 | 2,719,453 | 2,726,193 |
| Measurement | Total |
| Days measured | 363 |
| Days with good air quality | 237 |
| Days with moderate air quality | 125 |
| Days w/ poor A.Q. for sensitive groups | 1 |
| Days with unhealthy air quality |
| Pollutant | Total |
| Arsenic | 0.002% |
| Benzene | 0.030% |
| Carbon Tetrachloride | 0.002% |
| Lead | 0.002% |
| Mercury | 0.000% |
| City | Population | Air Quality Index | National Avg. |
| Mount Summit, IN | 408 | 28 | 44.0% |
| Wilkinson, IN | 439 | 28 | 44.0% |
| Cadiz, IN | 242 | 28 | 44.0% |
| Kennard, IN | 663 | 28 | 44.0% |
| New Castle, IN | 17,234 | 28 | 44.0% |
| Middletown, IN | 2,472 | 42 | 16.0% |
| City | Population | Air Quality Index | National Avg. |
| Keokea, HI | 2,471 | 15 | 70.0% |
| Merriam Woods, MO | 2,471 | 18 | 64.0% |
| Solomons, MD | 2,470 | 41 | 18.0% |
| Carthage, IL | 2,474 | 29 | 42.0% |
| St. Hedwig, TX | 2,474 | 49 | 2.0% |
| Middletown, IN | 2,472 | 42 | 16.0% |
Here are the best places to live in Indiana
Check out the 10 safest cities in Indiana
See the best places to live in Middletown
These are the 10 cheapest cities in Indiana