Several threads like this going on at the moment, here and in the UK.
Here on the Rogue River the water temp will run between 52 to 56 degrees year round. Air temp is, can be, quite a different thing.
1. 6 months = silk sock liners and SealSkin booties ... we'll come back to that.
2. 6 months = silk sock liners, light knee high wool sock and SealSkin booties.
Tight boots are a no-no, but the real no-no is sweat, yes you read that right. Even on a cold day the average male will 'sweat' close to a quart to a liter of water. You can't stop it, it is just who we are.
And your feet sweat, trust me even as you're sitting in front of your lap top your feet are sweating. Soooooo water against cold water = cold feet.
Been doing this for years and other the odd one off (get out of the water and stomp around to kick in body heat) you do # 1 or #2 above and your gold.
Why? The silk under sock wicks away the water (aka sweat) into the inner lining of the SS's. They move it out/away from your feet. Not unusual to find the inner's dry as bone and the exterior of the SS's to be damp.
Guys, drop a few bucks, you'll find I'm right. Get the 'sweat' away from your feet.