In my (German-made) car the temperature can be toggled up/down by one degree Fahrenheit. If I switch it to Celsius, an additional digit is displayed which shows either a 0 or 5 that lets me select the temperature in 0.5C degree increments.

To me, this is a pretty clear indication that people can feel the difference in half degrees Celsius (otherwise, why would the manufacturer bother with it?). And because of that, Fahrenheit is better for human-scale temperatures, as only two significant digits are required instead of three.