The Russian streltsy (shooters) of 17th century are usually depicted in winter uniform wearing fur hats and dress. What was their summer uniform?
That's not the winter uniform, it's simply the uniform, and was worn in all weathers.
It's unclear if the summer uniforms were just for the navy, or for everyone, but this is the earliest date I can find for any mention of a winter or summer uniform, of any kind in any country. The Swedish 17th century Caroleans did not have separate winter and summer uniforms, for example.