>>19088445Climate. If your country is freezing cold, then you can't grow cotton, so unless your country has easy trade access to cheap cotton, then chances are cotton clothing will be reserved for upper class trends.
If that's too hard though, you could just look at the materials your real world cultural analogue would be.
What's more important though is practicality. I can suspend my disbelief and just assume that your cotton clothing is just grown with a special breed of cotton that can survive the cold. If said cotton clothing does nothing to protect you from the warmth I'm going to start asking questions.
using the Kronies as an example, I could see them wearing something like this, at least during the snowy sub arctic winters, and shedding the trench coat for perhaps simple jumpers during the more temperate summer. Basing them off Anglos, since muh londoners, the sweaters could be made of wool and the trench coat made of Grey Herringbone tweed, both of which are made of wool, which could be fairly available on their island.