| 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 | Fairlington-Bradlee | Alexandria | Virginia |
| Air quality index | 49 | 49 | 58 |
| Pollution index | 2,776,590 | 2,776,590 | 1,533,792 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 194 |
| Days with moderate air quality | 166 |
| Days w/ poor A.Q. for sensitive groups | 5 |
| Days with unhealthy air quality |
| Pollutant | Total |
| Arsenic | 0.070% |
| Benzene | 0.020% |
| Carbon Tetrachloride | 0.010% |
| Lead | 0.020% |
| Mercury | 0.030% |
| City, State | Population | Air Quality Index | National Avg. |
| Forestville, MD | 12,100 | 49 | 2% |
| Friendship Heights Village, MD | 4,730 | 49 | 2% |
| Glen Echo, MD | 334 | 49 | 2% |
| Hyattsville, MD | 18,262 | 49 | 2% |
| Landover, MD | 23,124 | 49 | 2% |
| Alexandria, VA | 151,473 | 49 | 2% |
| City, State | Population | Air Quality Index | National Avg. |
| Pomona, CA | 151,807 | 85 | 70% |
| Escondido, CA | 149,912 | 61 | 22% |
| Lakewood, CO | 149,793 | 54 | 8% |
| Kansas City, KS | 149,755 | 58 | 16% |
| Pasadena, TX | 153,286 | 52 | 4% |
| Alexandria, VA | 151,473 | 49 | 2% |