@unchartedworlds here's a few things that I have been told about thermometers over the years that for some reason were not obvious to me:
To get the best indication of air temperature, the thermometer must be in the shade.
Breeze has no effect on the temperature of objects (like thermometers) that are not self heating.
The thermometer shows the temperature of the thermometer rather than anything else.
I hope this is of help.
I know almost nothing else about thermometers.