0°C is completely fine with jeans and a thick jacket, especially when it's sunny and there isn't much wind. It's cold, but there's probably not much ice or snow, if anything, probably mostly slush.

Compared to say -20 C where you should have a good ski jacket and ski pants, warm shoes and socks, generally multiple layers everywhere, winter gloves and so on.

It is also literally melting.

I've been in -37C snow shoveling. Since then 0C doesn't even register as cold to me

The northern half of the US laughs

The temperature that water freezes at is only fairly cold weather by a lot of people's perception.
I'd call it "chilly". No jacket for running to the mailbox, or if I'll be outside for half an hour or so. Light jacket otherwise. I don't expect it to snow, since it's not actually cold enough usually, and there won't be ice on the ground unless it's just warmed up.

So it might be "freezing", but that doesn't make it cold.

Many places in the US, particularly in the East and Midwest, experience average temperatures at or below freezing (32°F) in the winter, so while it's definitely cold, it's often not considered really cold. It's not until you move further towards 0 and the negatives that most people in that area feel really cold (like weather advisory levels). Of course the further north you go, the more normal those temps are. Likewise, it's definitely not unheard of for temps to hit 100°F (37°C) in the Southwest, but it would be considered pretty hot for much of the country, and even Texas suffers at sustained temps like that.

I would put it at a 3/10

We're not made out of water.

Everything about -10 is warm.