In most places, colorful clothing is something of a status symbol. Finer cottons and silks in bold colors denote the money it took to make such things in areas like Korvasin or Genfierz. In some regions, like the north or in Rutan, colorful clothes are slightly easier to come by but as a result aren’t as sought out. Considering the harsh climates in both places, it’s no wonder. Everything fades faster under the bright sun.
In more magically-inclined places, the clothing becomes even more colorful, as it’s much easier to change such things. In the south, people often wear breezier clothes, with more pieces and wrapped styles than the conservative middle/northerners.