Today I am going to do the companion posting to the last one. Men's costume in Latvia is not that different from region to region, but It would be good to provide what information there is to any who are seeking it.
Latgale, as you may have figured out by now, is not the most prosperous of the Latvian provinces, and it was under the Russian empire for part of its history, so there is some Russian influence on the clothing, particularly for the men, who dealt with outsiders and travelled more. Here is a map of Latvia showing the 5 cultural provinces. Latgale is shown in blue, Vidzeme in yellow, Kurzeme or Courland in orange, Zemgale in green, and Augszeme or Selija in rust. The differences are in part due to traits inherited from different ancestral tribes.
and sometimes a bit more complex. As the shirts were generally worn outside the pants, this was not very noticeable. Linen pants were worn for work and in warm weather. If a man could afford them, he would wear wool pants in cooler weather, or for dress. Wool pants tended to be of this cut below. Pants were always tucked into footcloths, socks or boots, unless, of course the man was working barefoot.
Aija Jansone et al, 'Ieteikumi Latviesu Tautas Terpu Valkatajiem', Riga, 2002
T. Razina, 'Folk Art in the Soviet Union', Leningrad, 1990