3D Diagramm, class of color legend

Hello,

I report temperature data over 6 month in a 3D diagramm like this

The temperature is shown on the z axis.

The class of the color legend is  given automatically. (-13.5/-10.9, -10.9/-8.4,...., 25/27.6)

Is it possible to choose the number and the range of the color legend class (for example -15/-12.5, -12.5/10, ... 25/27.5, 27.5/30) ?

Thanks for your help.

regards

Vincent