Wet is the enemy. Dry socks stay warm I start wearing 2 pair @ 20F.
Ride the bike, feet on the ground @0 F degrees transfer cold to the feet fast.
Feet & hands need the most protection.
Mittens are superior but can really suck riding a bike so I wear big mittens & wool gloves inside them for needed dexterity pulling off a mitten with my teeth. I use scarfs to keep cold out of neck & face.
The body core is more of a problem regulating to stay cool & I still often over dress my bodycore in below -0 F temps. I wear a lined vented hip length Nordica III All Terrain rain/windbreaker with liner removed, back vent zipped open, usually & regulate my body core with my rain coat frt.zipper.
I wear a hoodie instead of the zip-in liner.
Good long johns, or double layer more affordable L J's.
I wear this ridiculous hat below zero. Yes, it has red pom poms
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