system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why doesn't the windchill affect my thermometer?

My friend and I were talking about this yesterday and again this morning. It's -31oC with a -15oC Windchill. Why wouldn't the windchill change the temperature in a vehicle thermometer or on a house or somewhere that it would be in the wind?
gpt
Wind chill is a made up number; it has nothing to do with the actual temperature.  It indicates (sort of) what it would feel like to stand in a room with non-moving air at a given temperature.  So if it's 30 out and there's a 20 knot wind blowing, your body would lose heat as though it was 20 out and there was no wind blowing.  

So, why does it feel colder to a human but not to a thermometer?  Fairly simple - a thermometer becomes the temperature around it.  When the wind blows, the thermometer doesn't lose any more heat - in our example above, it's already at 30 degrees just like the air around it and moving the air around doesn't change the temperature. 

However, as a human, you're trying to keep your temperature around 98 degrees; this is quite a bit warmer than the 30 degree air around you.  You lose heat at a certain rate when the temp is 30.  If the wind blows on you, you lose heat even faster - as though the temperature were lower.