So I'll begin by saying have not been able to try this yet, I plan to when I get off work.
But, I have to say, why are you waiting at one spot for so long? While you are waiting the other spot my be right and you are missing it. You start with 20 to choose from when you start right? From what I understand the weather has a chance to change three times a day so if its not the right weather/time then go to another location and check there.
As for real life site seeing if I go to the Eiffel tower and it starts raining I'm not going to set there and wait for the time/weather to be right. I'm going to go see/do other things until the time/weather is right.