Arlington and other parts of the D.C. area are under a Frost Advisory tonight.
Temperatures are expected to tip into the 30s early Tuesday morning, potentially damaging sensitive plants.
From the National Weather Service:
FROST ADVISORY IN EFFECT FROM 2 AM TO 8 AM EST TUESDAY… THE NATIONAL WEATHER SERVICE IN BALTIMORE MD/WASHINGTON HAS ISSUED A FROST ADVISORY… WHICH IS IN EFFECT FROM 2 AM TO 8 AM EST TUESDAY. * TEMPERATURES… IN THE UPPER 30S. * IMPACTS… POTENTIAL DAMAGE TO SENSITIVE PLANTS. PRECAUTIONARY/PREPAREDNESS ACTIONS… A FROST ADVISORY MEANS THAT WIDESPREAD FROST IS EXPECTED. SENSITIVE OUTDOOR PLANTS MAY BE KILLED IF LEFT UNCOVERED.