The Köppen–Geiger climate classification made simpler (I hope so)

[ascanius]

You mean I should say, very cold, cold, hot... instead of using the colours? I thought it would be less confusing to use the latter.
Or that I should indicate the names of each colours to avoid confusion?

Me personally I think just using the temp range would be better, like over 35C, 28 to 35C etc. You could do severely hot, very hot and the others too and it would work just as well, using numbers are just my personal taste. Don't get me wrong I like the use of the color key you supplied but with the way it is now I cannot tell which dark orange your referring too. By the way you also have 10 colors for the elevation key but only 8, unless I counted wrong, for the other first key.