Aero Weather is an application for Windows Vista and Windows 7 that changes the color scheme of the operating system based on current weather conditions in your location, but for that to happen you must meet two conditions, one is having a version of Windows that supports Aero ie Home Premium, Professional, or Windows Vista Ultimate or Windows 7 and the other is that climatic conditions only supports U.S. cities.
The first time you run Aero Weather after installation you get a window confinguración where basically you have to enter a zip code somewhere in the U.S. to get the weather conditions there.
Three other additional settings. You can change the color scheme based on temperaturao to weather conditions, you can also define the range of colors and if the night mode should be enabled or not.
Link to download Aero Weather.