I read this short story within the last year or two, almost certainly in a short story collection. It was relatively old, possibly from the '60s or '70s, but it could have been from the '50s or '80s too. I think the collection was by one of the bigger names like Frederik Pohl, Larry Niven, or Ray Bradbury, but I'm not 100% on that.
I don't remember how exactly it happens, but a man is in a phone booth and receives a call that isn't meant for him. The person on the other end says that the world is going to end (probably a nuclear thing, though I can't remember exactly). He then spends the rest of his day like there's no tomorrow, without telling anyone about the upcoming disaster.
I believe he passes the day with his girlfriend, but I can't remember if he tells her about the call or not. They might have watched the sunset on top of a roof, but that could be from a different story. I remember it being a very peaceful, touching story. It's a lot like "The Last Night Of The World" by Ray Bradbury. It's definitely realistic fiction; there are no fantastic elements. I don't think it's related to the 1988 movie MIRACLE MILE, Larry Niven's short story INCONSTANT MOON, or Robert Heinlein's THE YEAR OF THE JACKPOT, despite the similarities. Any help would be much appreciated!