How to get Discrete plugin with gradient color mapping (w/o mapping each single value)


I mapped my CO2 values in a Discrete graph.
Values are mapped with 1) a range and 2) a color. As I have just a 5 different ranges, this is OK.

I want to do the same with the outside temperature.

How can I accomplish this without mapping each single value to a color?

I want a high resolution of steps, starting at blue (for very cold) to red (for very hot).
Exactly what you can find in field tab of the Gauge chart.
(Can’t find this at the Discrete chart)