People with cold-sensitive plants urged to move them inside.
The National Weather Service in Sterling, Virginia. has issued a freeze watch for the region. It will take affect late Monday night and continue into Thursday morning. The areas covered are Frederick, Washington and Carroll Counties in Maryland, and Jefferson and Berkeley Counties in West Virginia.
The agency says temperatures are expected to drop into the low 30's early Tuesday morning.
Residents who have cold-sensitive plants are encouraged to bring them inside.
The Weather Service says a watch means that conditions favorable for sub-freezing temperatures.