system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How can the weather be below freezing AND 100% humidity?

Doesnt the temperature mean that fog can't be "humidity"?

Isn't humidity moisture and doesn't moisture crystallize into a solid form below 32 degrees?
gpt
There are two forms of humidity: relative humidity (%) and absolute humidity (grams of water/liter of gas). Something that is at 100% humidity means that it is holding as much water as possible, no matter how little that may be.