1114
Scary
(files.mastodon.social)
alt text
Comic strip of a ghost and a person with the American flag pasted on the head. The ghost repeats "Boo!" in the first three panels without getting any reaction, but when it in the fourth panel says "kg, cm, km, °C" the American gets scared and screams "AHHHH!!!".
Edit: fixed alt text
Percent of how close it is to 100% hot out.
But in seriousness, 100 was supposed to be based on the human body temperature. When it's above 100, it's harder to cool yourself off.
It's based on how humans react to the heat, you need active cooling such as sweat, moving air isn't enough above 100 degrees. 100% hot out is just a silly way of putting it.
I sweat when it's way below 100°F because I haven't done any sport in quite a while. Checkmate Fahrenheiters.
Supposedly the temperature salt freezes at, but it's off by quite a bit. I'm not sure if it has any implications for staying warm in cold weather.