I've seen lots of wargamers paint vehicle windows all varieties of blue, green, silver, and even white, and many use mixtures of several or all of those. But as you pass cars during your day, have you ever really looked at their windows and thought about it? Probably not, but here's what you would see:
"But wait!", I hear you cry. "Military vehicles are different!" Au contrair!
As you can see, vehicle windows very often look quite dark. Only as you approach the vehicle does the reflection of the sky make it appear lighter.
Buildings are a somewhat different matter. Large office buildings, especially at a distance, often appear to have dark windows. Here's the AIG building, more than a mile distant:
Needless to say, buildings that have a mirrored surface look different, as they almost always reflect the sky and landscape and so always look light-colored:
Smaller buildings can go either way, light windows:
Residential buildings can also go either way, lighter appearing due to shades or blinds inside the windows:
Or a darker appearance:
Or often, both:
More next time.