White Balance Dilemma

[Lrk]

This is also a time-lapse question.
Let's start with a question that could solve the problem: In rapidly changing light conditions(sunset), if i choose a particular white balance temperature, fit for the beginning of the shooting interval, will this negatively affect the photos shot towards the end of the interval?

So here's the story. I want to shoot timelapse over the course of about 45-60 minutes. The shooting location is a rooftop, limited acces, so this is probably the only shot at it i'll get. Yesterday i did a test shot, with white balance on auto(stupid me). The colors came out great(personal opinion), but i wasn't able to determine what color temperature the camera(Nikon D90) used. Any idea what program i could use to find out?
I can't shoot in RAW because the shooting setting i chose (4" shutter, 1 sec between photos, sometimes doesn't give the camera enough time to download the pics to the laptop)
This is one of the shots:

I didn't have the tripod, so it got blurry.
I am confused because it is cloudy and it's also a sunset(the sun sets a little to the left of the shot) and the temperatures for the two settings are pretty far apart. This shot was taken at 18:45, which is about in the middle of the interval i planed(18:20-19:20).
Thanks.
PS: Sorry for the info overload.

 

[Garbz]

No there's no easy way to tell what the white balance was without a RAW file. Though looking at the picture it's very close to daylight. Possibly around the 4000k mark. Ignore cloudy vs sunny settings. Neither apply in this situation. Your scene is directly lit by a deep blue light (much colder than the coldest setting on any camera), halogen lights, xenon lights, and mercury vapour lights. Each has a widely different colour balance.

Your decision comes down to picking the option that looks best. For a timelapse, auto would be the worst choice. Having the colour of the lights change during the scene would look horrid. Personally I pick daylight. Having a green / purple city does not accurately reflect the yellow glow that it actually would have if your camera is locked in daylight.

This may be my personal opinion only but daylight not only would not negatively effect the scene during night but would actually look damn good.

Here's an example of the city at night using a daylight setting: