Why were hats so prevalent in public as opposed to now?

by MissyAggrivation

I’ve been watching a lot of documentaries about World War I and looking at fashion from late 19th century to mid 20th century and it seems that everyone is wearing a hat of some sort. Why?

Kryptospuridium137

Hopefully someone can add more, but I got curious about this just last night.

You might find this post by /u/chocolatepot interesting.