How can I check if my weatherproof windows are completely sealed?

Completely sealed weatherproof windows are always completely clear. There should be no steam or moisture on any of the outer panels or in the middle. It is true that you can have completely fogged up interior windows but that should always be due to the fact that you are using hot water or are heating water within your living quarters. If you start to see condensation in the middle of a supposedly weatherproof window, you have irrefutable evidence that the window's weatherproofing ability has been compromised and it is time to exercise any warranty rights you may have with the installer.