If you mean the Sky Happenings - Weather edition widget, then I think the answer to both your questions is No.
I'm pretty sure that this widget can only show US weather. If you enter the zip code 38820 you will get the weather for Algoma, Mississippi, since there is no way to set the country to be other than the US.
I have a couple of instances of this widget in my Morning channel. It is interesting (although not useful) to see what the weather is like in various US cities.