Why did they meet at 4.00pm?

I actually quite liked this film, probably because I share certain misanthropic qualities with the characters, and because I recently moved away from LA and am missing the city.

But the one thing that really irritated me about the movie was the timeline - if they met at 4.00pm at La Poubelle, there is no way in the world they would have even made it to the subway station before it started to getting dark, let alone had time to wander around downtown in daylight. The sun has set by 5.00pm in LA on new year's eve. Why not just have them meet at say 2.00pm? Would that have ruined the timeline for the rest of the movie? Or are we supposed to just pretend that thanks to the magic of movies the sun didn't set until 7.00pm on this particular winter's day?