| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 24°F | 42°F | 32°F | 3.2" |
| February | 25°F | 43°F | 33°F | 2.4" |
| March | 33°F | 55°F | 43°F | 3.9" |
| April | 43°F | 68°F | 55°F | 4.1" |
| May | 52°F | 75°F | 63°F | 4.3" |
| June | 60°F | 82°F | 71°F | 4.8" |
| July | 64°F | 85°F | 74°F | 6.0" |
| August | 63°F | 84°F | 73°F | 4.0" |
| September | 57°F | 79°F | 67°F | 3.2" |
| October | 46°F | 67°F | 56°F | 3.9" |
| November | 36°F | 57°F | 46°F | 2.7" |
| December | 29°F | 46°F | 37°F | 4.1" |
| Index | Crellin | Maryland | National |
| Air quality index | 36 | 43 | 42 |
| Pollution index | 1,427,850 | 5,342,367 | 2,726,193 |
| Measurement | Total |
| Days measured | 364 |
| Days with good air quality | 337 |
| Days with moderate air quality | 27 |
| Days w/ poor A.Q. for sensitive groups | 0 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.003% |
| Benzene | 0.004% |
| Carbon Tetrachloride | 0.001% |
| Lead | 0.001% |
| Mercury | 0.010% |
| City | Population | Air Quality Index | National Avg. |
| Loch Lynn Heights, MD | 475 | 36 | 28.0% |
| Bayard, WV | 250 | 36 | 28.0% |
| Kingwood, WV | 3,163 | 36 | 28.0% |
| Mountain Lake Park, MD | 2,028 | 36 | 28.0% |
| Hutton, MD | 67 | 36 | 28.0% |
| Crellin, MD | 60 | 36 | 28.0% |
| City | Population | Air Quality Index | National Avg. |
| Smithville, AR | 60 | 45 | 10.0% |
| Campo Bonito, AZ | 60 | 47 | 6.0% |
| Carrick, CA | 60 | 42 | 16.0% |
| Paskenta, CA | 60 | 41 | 18.0% |
| Jeisyville, IL | 60 | 40 | 20.0% |
| Crellin, MD | 60 | 36 | 28.0% |