On one of the busiest travel days of the year, a combination of dismal weather and the crush of holiday travelers was creating gridlock at airports along the East Coast on Wednesday afternoon.

A combination of low visibility, dense fog, thunderstorms and wind threatened delays to air travel throughout the day, according to the Federal Aviation Administration, and the combination of weather and the numbers of traveling masses created serious congestion at the major New York City area airports.

At LaGuardia, low visibility caused arriving flights to be delayed on average 2 hours and 35 minutes as of Wednesday afternoon, according to the FAA’s delay tracking website. Departing flights were late leaving the airport by an average of 1 hour 35 minutes, according to flightaware.com

Passengers were also advised of delays in the terminals at LaGuardia and Kennedy: The Port Authority on Wednesday sent out alerts advising travelers to allow for extra time to check into their flight and get through security due to long lines.

As throngs of holiday travelers flocked to reunite with loved ones on Wednesday, LaGuardia had the highest percentage of flight delays in the country: 39 percent of the airport’s departing flights and 35 percent of arrivals were late as of 4 p.m., according to flightaware.com, representing 419 total delays. In addition, 111 flights had been canceled by early afternoon.

“Can’t remember the last time my flight out of #JFK/#LGA was on time,” groaned Twitter user @cedxc2005, adding some hashtags for good measure: “#nycliving #flyingisfun #sarcasm #Christmastravel.”

“I’m going to start DJing things to do, games to play, carols to sing, podcasts to listen to while you’re delayed at #LaGuardia airport #nyc,” tweeted user @lgron.

Some saw the delays as an opportunity for Christmas caroling. A few Spirit Airlines employees at LaGuardia were apparently trying to stir up holiday cheer among passengers when they began singing “Jingle Bells” over the loud speaker, a moment captured by several appreciative travelers.

At Kennedy Airport, delays were not as severe, but still persisted throughout the day: Inbound flights were delayed at their origin airport by an average of 1 hour and 9 minutes, according to the FAA, but departures were only delayed by about 30 minutes. Kennedy saw 192 delayed flights as of 4 p.m. and 11 percent of departures were late, compared to 17 percent of arrivals, according to flightaware.com.