JoAnn Paules said:
Alt+0186 is º, the ordinal symbol. It's used in some languages the way we
use "th", "rd", "st", and "nd".
Alt+0176 is °, the degree sign. This is used in Celsius and Fahrenheit (but
not Kelvin, where a capital K is used without a degree sign).
Note that all Alt-codes have to be entered on the numeric keypad, not on the
typewriter number keys.