I saw you responded in the other post, thanks. I'm old enough to have learned the imperial measurement first then introduced to the metric system, but am better now with the metric other than temperature.
What I did next to my Fahrenheit thermometer in the house was a little sticky note with a few cross references 20F>-5C, 32F>0C, 40F>5C, 60F>16C, 80F>27C.
Now I'm pretty accustomed to approximating the temp by rounding it out. Besides the temp sensor in your car can be affected by other outside factors.
Might help out while you adjust.