The warning covered Western Chester, Eastern Chester, Eastern Montgomery and Lower Bucks.

“Temperatures are rising above freezing,” the National Weather Service says.

What to do if there is a frost watch or warning

Frost warnings are issued from May to October (but can be extended if necessary), when low temperatures are expected to be between 29 and 32 degrees. If there is a risk of temperatures falling below these thresholds, a frost watch may be issued a few days in advance.

According to the weather service, if a frost warning or watch is issued for your area, there is little you can do to protect the plants. If you can move your sensitive plants indoors, do so because freezing temperatures will likely kill them, depending on the severity of the conditions.

Advance Local Weather Alerts is a service provided by United Robots, which uses machine learning to compile the latest data from the National Weather Service.