| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 28°F | 47°F | 37°F | 2.7" |
| February | 29°F | 50°F | 38°F | 2.3" |
| March | 37°F | 60°F | 47°F | 3.2" |
| April | 47°F | 71°F | 58°F | 3.4" |
| May | 56°F | 78°F | 67°F | 4.6" |
| June | 67°F | 87°F | 77°F | 5.3" |
| July | 72°F | 91°F | 81°F | 4.2" |
| August | 70°F | 90°F | 79°F | 3.2" |
| September | 63°F | 83°F | 72°F | 3.5" |
| October | 52°F | 72°F | 61°F | 5.0" |
| November | 40°F | 61°F | 50°F | 2.5" |
| December | 33°F | 52°F | 42°F | 3.8" |
| Index | Brentwood | Washington | District of Columbia |
| Air quality index | 47 | 47 | 49 |
| Pollution index | 5,554,010 | 5,554,010 | 5,554,010 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 209 |
| Days with moderate air quality | 145 |
| Days w/ poor A.Q. for sensitive groups | 10 |
| Days with unhealthy air quality | 1 |
| Pollutant | Total |
| Arsenic | 0.010% |
| Benzene | 0.060% |
| Carbon Tetrachloride | 0.010% |
| Lead | 0.004% |
| Mercury | 0.010% |
| City | Population | Air Quality Index | National Avg. |
| Maryland City, MD | 17,681 | 46 | 8.0% |
| Fort Meade, MD | 11,340 | 46 | 8.0% |
| North Laurel, MD | 24,856 | 46 | 8.0% |
| Rockville, MD | 68,155 | 47 | 6.0% |
| White Oak, MD | 15,655 | 47 | 6.0% |
| Washington, DC | 701,974 | 47 | 6.0% |
| City | Population | Air Quality Index | National Avg. |
| Vancouver, BC | 694,440 | n/a | |
| Boston, MA | 689,326 | 43 | 14.0% |
| Denver, CO | 715,878 | 58 | 16.0% |
| El Paso, TX | 679,879 | 53 | 6.0% |
| Detroit, MI | 672,351 | 56 | 12.0% |
| Washington, DC | 701,974 | 47 | 6.0% |
Here are the best places to live in District of Columbia
Most Dangerous Cities In The US
Check out the 10 most dangerous cities in District of Columbia
Most Dangerous States In The US