Two things to think about:

Heat-sink, are you riding with clipless pedals? The metal cleat and metal pedals will act as a heat-sink, drawing the heat out of the bottom of your foot. My wife has poor circulation; on cold days with clipless pedals, you can look at the bottom of her foot and see exactly where the cleat is on her shoe - white square. Solutions, use platforms in cold temps or get wool inserts for your shoes.

Shoe covers, I ride shoe covers for temps under 30F - Blitzen I recommend this versus doubled-up socks since this can compress the foot and make circulation worse.

Sidenote, I run extra hot, so my temp range and comfort level are atypical.