It can be -20 C and you can be still fine with jeans and a jacket if it isn't windy.

What I'm saying is temperature alone doesn't tell you the whole story.

But so is 100°F completely fine with a shirt and shorts and some shade.

So basically: |0°F| > |100°F|, where | is the mathematical absolute operator.

0°F is really cold, while 100°F is merely somewhat hot.

https://www.brennanshvac.com/article/humidity-temperature-strange-link-know#:~:text=In%20cold%20weather%2C%20high%20humidity,of%20warm%20air%20around%20you.

Humidity. I'm guessing you don't live in a humid place because freezing temps are horrifically cold here. You will need a winter coat and multiple layers of your going to be outside for a while. I layer long Johns under my pants and wear my parka and a light jacket as well as 2 layers of socks. Everytime a northerner comes here they are shocked at the cold/heat. That's because the air here is full of water to the point that you will actually get wet just from the humidity, not even sweating.