| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 23°F | 36°F | 29°F | 4.0" |
| February | 23°F | 36°F | 29°F | 3.7" |
| March | 33°F | 50°F | 40°F | 5.2" |
| April | 44°F | 63°F | 52°F | 4.8" |
| May | 54°F | 70°F | 61°F | 5.1" |
| June | 61°F | 77°F | 68°F | 5.8" |
| July | 66°F | 81°F | 73°F | 4.0" |
| August | 64°F | 79°F | 71°F | 4.3" |
| September | 56°F | 70°F | 62°F | 4.4" |
| October | 48°F | 62°F | 55°F | 5.6" |
| November | 37°F | 51°F | 43°F | 3.8" |
| December | 29°F | 41°F | 35°F | 5.0" |
| Index | Middletown | Maryland | National |
| Air quality index | 40 | 43 | 42 |
| Pollution index | 5,553,870 | 5,342,367 | 2,726,193 |
| Measurement | Total |
| Days measured | 362 |
| Days with good air quality | 306 |
| Days with moderate air quality | 54 |
| Days w/ poor A.Q. for sensitive groups | 2 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.004% |
| Benzene | 0.070% |
| Carbon Tetrachloride | 0.010% |
| Lead | 0.410% |
| Mercury | 0.070% |
| City | Population | Air Quality Index | National Avg. |
| Adamstown, MD | 2,130 | 40 | 20.0% |
| Brunswick, MD | 6,364 | 40 | 20.0% |
| Linganore, MD | 9,988 | 40 | 20.0% |
| Rosemont, MD | 325 | 40 | 20.0% |
| Antietam, MD | 45 | 40 | 20.0% |
| Middletown, MD | 4,694 | 40 | 20.0% |
| City | Population | Air Quality Index | National Avg. |
| Fountain Hill, PA | 4,693 | 42 | 16.0% |
| Stock Island, FL | 4,692 | 34 | 32.0% |
| Dexter, MI | 4,691 | 40 | 20.0% |
| New Freedom, PA | 4,691 | 41 | 18.0% |
| Woodmore, MD | 4,698 | 47 | 6.0% |
| Middletown, MD | 4,694 | 40 | 20.0% |
Here are the best places to live in Maryland
Top 10 cities in Maryland with the best education system
These are the 10 most affordable cities in Maryland
10 best cities to buy a new house in Maryland