According to the Wikipedia article, "The degree symbol is a typographical symbol that is used, among other things, to represent degrees of arc (e.g. in Geographic coordinate systems) or degrees of temperature. The symbol consists of a small raised circle, historically a zero glyph."
A common problem is typing or inserting the degree symbol on a standard computer keyboard.
Here is how it's done within Microsoft Windows: hold down the ALT key and type 248 on the numeric pad, then release the ALT key.
If you have a Mac, hold down the Option key (usually labelled ALT as well) and type a zero.
If you're using a laptop without a numeric pad, copy and paste this character: °