Two days ago, I was with my wife and kid at a lake where we hiked a little and I took some photographs. It was in the middle of a snowstorm and I needed extreme white balance values to get correct color. So yesterday, as I saw that the sky was clear and the sunset would give nice color I went there again to make photos at more or less the same time. The differences are astounding. Where two days ago this very distinctive tree looked like this:
Yesterday it looked like this:
Quite different indeed.
Another example (bigger version in the link):
This just illustrates how important it is to be somewhere on the right time to catch the light and the feeling of a place. You can see more images from this place in the flickr set here.