Degree is also for -1 :P so it's 1 degree, -1 degree, the rest is degrees, like neal said.

Hi 1 degree. Everything else is degrees, including 0. The only exception to this is that you can also use words to describe a fraction of a single degree, but when you use numbers, or if it is greater than 1, then it is always degrees. For example, 'half a degree' but '0.5 degrees'. 'one and a half degrees', '1.5 degrees'.)