Reddit reviews BUFF Unisex New Original Multifunctional Headwear, Elektrik Blue, One Size

Here's what I wear in sub-30 weather starting from the bottom:

Wool socks, sandwich bag over each sock (put it on under the shoe and then tie the top of the bag so it doesn't hit your chain), thermal bottoms, pants, tshirt or thermal top, light sweater or flannel, shell jacket (ie something to keep moisture off of you, heat contained, and serve as a wind brake - don't bother with anything heavy unless it's around 0f), shell mittens and nothing else on my hands, buff around my neck, buff over my head covering ears and skull, bike helmet.

I biked to work this morning at 7am with that outfit and felt fine the whole ride. Even showed up slightly sweaty.

When the temperature dips under 20f I'll add liner gloves under the mittens, a scarf, and a hat with ear protection.