First off, you always need a base layer, and it should NOT be made of cotton. Pick a nice spandex or polyester undershirt. Smartwool and Icebreaker are two recommended brands.
For your bottoms, depending on the temps and the hike, you’ll need one, two, or all of these things… wool base layer, fleece leggings, spandex layer to go under your waterproof pants. EMS makes affordable trail pants (and they usually have decent sales or coupons going on). You’ll see that we love the funky leggings – I typically wear my REI base layer underneath them or my fleece leggings. You should always plan to butt slide on ice during cold weather hikes, so if you don’t like a wet butt, waterproof pants are the way to go!
I can’t recommend a vest enough. It keeps your core warm while keeping the rest of your body cool. I wear one of these, always. Sometimes it’s puffy, sometimes it’s not. I’ve been able to score some great name brand vests at resale shops. I’m currently into Old Navy vests for my hikes, and I recommend them. They are cute and keep me warm!
For your outer layer, you’ll want a waterproof rain jacket and a puffy jacket.
For your extremities, you’ll want a warm hat, neck buff, waterproof gloves and or mittens, and wool socks. I also always bring hot hands hand and feet warmers with me!
Here are some of the products I recommend for cold weather hiking!