At the end of the episode, Elaine says "Jerry, it's 3:00am. I'm at a c*ck fight. What am I clinging to?" But then it cuts away to George's apartment where Elaine's boyfriend and George's girlfriend are talking, but the shot outside is clearly in the day time. And who goes visiting people at 3:00am? Kinda weird.
I'll admit it shouldn't be day...but whether or not it's 3:00 A.M. wouldn't have anything to do with any of the characters visiting another. The Sienfield characters are strange people.
How do you know where Elaine was calling from? She doesn't necessarily have to be in New York City. Also, the next scene doesn't necessarily have to be directly, the moment after she called.
Have you ever been to NYC? The city never sleeps and people go out at all hours of the night. It's almost like everlasting social hour. They just don't stop.