Are you tired of having a thermometer outside your window and go check it before getting out? Just take a look at your Linux screen and keep an eye on the weather :
Of course, Linux doesn't force you to do anything, so you can place this anywhere you want on your screen, or just not have it at all (after all, isn't it nicer to have a look through your window?). You can select the place where you live (or anywhere else) in a complete list of locations (OK, I cheated, I chose Honolulu for the screen capture, it's 2°C right now in Paris!).