My low in AAco was 13 when I left. Might've clicked down to 12 since.
BWI seems to have recorded a low of 21. A bit strange. They're usually colder than my warm location.
Andrews reported 13.
Even Pax River was 16
link: https://forecast.weather.gov/obslocal.php?warnzone=MDZ014&local_place=Millersville MD&zoneid=EST&offset=18000
ETA: Manassas 4 f. (!) IAD 10 f.
another link: https://forecast.weather.gov/obslocal.php?warnzone=VAZ054&local_place=2 Miles SW Washington DC, Reagan National Airport VA&zoneid=EST&offset=18000
(apologize if this has already been covered somewhere)