[Tagging] Temperature tag

[Warin]

The wiki page for temperature 
https://wiki.openstreetmap.org/wiki/Key:temperature has been empty for 
some time.. I've taken the plunge and made some entries .. see what you 
think!

Any ideas for improvements will be gratefully recived. Critisium without 
a suggestion as to how to improve, less so, but better than nothing.

You can, of course, make you own entries directly to the page.