I look at “Dew Point” to get a feel of the Humidity, and, like most people, I am not interested in the actual temperature of the object that's collecting the condensation. The (custom) color scale which I have for Temperature is completely useless when applied to Dew Point. In fact, it’s worse than useless – it’s misleading. IMSO there needs to be a dedicated custom color scale for Dew Point which is completely independent from the Temperature’s scale. I had in mind something like this:

Dew Point of:
0°C – White
10°C – Light Blue
20°C - Dark Blue
30°C – Purple
40°C – Deep Purple

A color scale like that makes sense to me. (Any) custom color scale for the Temperature’s (which is useful) cannot also be a good fit for the Dew Point.