As soon as fall breaks toward winter and outside temperatures drop, some windows in your home may appear a bit cloudy. Depending on where the fog is occurring, the problem may be as simple as excess moisture developing due to the difference in indoor and outdoor temperature or it might be more serious because the window seal is failing.
Condensation on the Glass Surface
Condensation on glass surfaces happens, for example, on a hot humid day when moisture may accumulate on the exterior side of your windows. Likewise, on a very cold day, moisture can build up on the interior side of your windows. Condensation on your windows can be worse when the outside temperature is below the dew point of the indoor air. Water or frost appears when warm moist air comes in contact with colder dry air.