system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why is 60 degrees indoors so much colder than 60 degrees outdoors?

I'm going to guess this has something to do with sunlight... but I don't really know. I would think that 60 degrees is 60 degrees. That certainly doesn't FEEL like the case. 60 degrees indoors is freezing. 60 degrees outdoors feels just fine.
gpt
How any given temperature makes the human body "feel" is related to humidity. Air conditioners lower the temperature by removing the humidity from the air. That is why air conditioners have a drip line. The water you see dripping from an AC unit is the humidity that has been removed from the environment.

Low humidity makes you feel cooler while high humidity makes you feel hotter. When the humidity is low your body sweat can evaporate easily. Body sweat evaporation is how the body regulates its temperature. When the humidity is high your body sweat cannot evaporate because the air is already full of water. When your sweat cannot evaporate it makes you feel very hot and sticky.

**It is all about the humidity.**