Flightstats.com, a website that keeps track of real-time flight data, said there were almost 7,000 flights delayed on Monday and another 400 flights cancelled.
The airport with the highest number of delays was New York's LaGuardia Airport. More than half of its flights, 52.67 percent were delayed on Monday.
Close behind was Fort Lauderdale with 48.84 percent of its flights delayed and then Orlando with 47.29 percent.
As of 5 a.m. on Tuesday, there were 50 cancellations and 124 delays, FlightStats.com said.