How to connect Temperature value (+ranges) to Color? #LookupCHOP?

Hello everyone!
I am learning touchdesigner since a couple of weeks now (self-taught). Currently I am trying to visualize the temperature curve of a day with color. Certain ranges have different colors, I want to assign them to “comfort ranges”.
For example 18-24°C (nice) = green; 37+°C (way too hot) = magenta etc.
I prepared a table from 55°C to -33°C and added the r g b values for each range.
With a noise I generated a “realistic” temperature curve to test how my ideas could be realized.

I created a sketch to explain the concept:

This is the table and how I created the color range, with a math I translated the 0-255 rgb values to 0-1:

I thought I could solve this nicely with CHOPS.
My problem is, that somehow the temperature in the outcome is incorrect and either too high or low. When I change the index range in the Lookup Chop the rgb channels are going crazy. I don’t understand, where the mistake is or if my approach is just completely wrong.
The noise generates temperature between ~9-14°C but in the lookup it is suddenly around 28°C.

The color seems to be correct for 28, but the 28 is wrong.

Does someone have any ideas where the problem could be?
Thank you!

Convert the temperature to TOP and use the LookupTOP with a ramp. (You can also use the LimitTOP to normalize the valuesv[bring them between 1 and 0] for the lookup.