Officials said the Code Blue began at 3 p.m. and will last until further notice.
A Code Blue is declared when the forecast shows either a wind chill of 20 degrees or below or a temperature of 32 degrees or below with precipitation.
During Code Blue, city officials implement 24-hour outreach to find people living on the street and transport them to indoor spaces.
People are also allowed to stay inside emergency housing all day and additional shelter beds are provided.
If you are concerned about someone who appears to be experiencing homelessness and is out on the street, call the city's Homeless Outreach Hotline at 215-232-1984.
Learn more about a Code Blue at phila.gov.