It was canceled due to weather.

I flew ORD-LGA last night on AA and our flight was delayed due to weather, though not by very long. A friend's flight last night from MDW-LGA was also delayed for the same reason.

Though the skies were clear, we were bouncing all over the place when we got near NYC, and the pilots said that ATC had to significantly reduce the number of arrivals and departures at the NYC airports.

Plenty of times I've been in this situation, where weather is cited as the problem at the arrival city, but the skies are clear. It's possible, and it happened last night.

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