Airport officials said they advised by the airlines in that decision.
There was no immediate word on when flights would resume.
U.S. Airways said "Our desire is to resume operations on Tuesday. However, we cannot say at this time whether or not that will be possible until we are able to assess the storm's full impact."
Southwest Airlines said "The resumption of service at Philadelphia will be contingent upon the condition of the runways, taxiways, and airport services."
Philadelphia Airport officials said they strongly urge all travelers to contact their airlines for flight status, call 1-800-PHL-GATE or visit http://www.phl.org.