window condensation

[Supervinnie40]

Do you drive at night often? Or only during the day?

When the air is warm it can absorb more water, but when the air cools the relative humidity goes up. When it reaches a certain point the air can't hold the water anymore and condensation will form on a surface (like the windows).
When you drive during the day (and there is a high humidity), the warm air gets inside the cabin, when it turns really cold at night, it needs to get rid of the moisture in the air because it has cooled down.

Might not be the case, but I just thought I'd throw it out there...