I have been riding in 20-30 temps about 1.5-2hrs every day at 5am. My feet tend to get very cold easily. For example when ice fishing I wear -80 degree Baffin boots and I can only be out for a few hrs in temps of 10 above. Anyway my set up is this. Pair of serius Hyperlite storm sock, liner socks. Then a pair of Darn Tough mountaineering socks. This is for 30 temps. I add plastic bread bags over the socks in the 20s. I then put this in a pair of Keen Bike shoes that kinda look like a sandle because I have so many socks on. Then over this I put on a pair of Outdoor research Huron neoprene snow shoe covers and finally a pair of Gore bike shoe covers. Depending on the temps today it was low 30s and almost snowing but raining I just wore the hyperlite socks, darn tough socks in a shimano regular bike with the Huron snow shoe covers and my feet were just fine, not really cold and dry. Every chemical warmer I have put on my toes is freezing cold when I get home, they were worthless. I think the hyperlite socks seem to help, I thought they were going to be worthless but they appear to work for me.