18:36 I am a journeyman leather/fur smith, and I specialize in historical garments. Fur-in or fur-out depends entirely on the kind of fur you are using.
Rabbit or sheared beaver is good for inside linings. Bison, for example, you want on the outside because they have multiple layers of hair on the hide that function exactly like the layers of clothes you would wear. Turning these kinds of skins fur-in would be like wearing your base layer on the outside and your shell layer against your skin.
So make sure to know how to use the fur properly before you pay an arm and leg for it.

Great video. The biggest difference for me between my modern bad weather gear and my medieval stuff is the length of the clothing. All my medieval kit is wool and linen, but it is usually at least knee length, and the top most layer, a tight fitting woolen hood with mantle over the shoulders. It needs to be practical for handling and riding horses too.

Side note: If you stuff your shoes with grass, use STRAW, not hay.  Straw is bedding; hay is food.  You use straw to make insulated cat shelters because hay will absorb moisture.

"Sometimes you may need to go on an adventure when it's cold outside."
Cut to: one of the many historical paintings of Napoleon's Retreat from Moscow captioned simply: DON'T.

I'm not a reenactor (anymore) but I do a lot of out door adventure sports.  I just wanted to point out that if you are very active out in the cold and have a moisture wicking base layer, weather it's a modern material or a historical one,  it's important to hydrate. Even if you don't think you need to. You won't notice how much you sweat and how much water you lose until it's too late.  This can cause dizziness, confusion, and muscle cramps.

A point of emphasis for the base layer; a snug fit is preferrable to a loose fit.  The base layer's job is simply to facilitate the moisture to the next outer layer away from the skin.  If the base layer is loose fitting it cannot perform this task as quickly or efficiently.  For this reason, as well, a thicker base layer is not typically more beneficial.  And, as pointed out in the video, avoid cotton as much as possible.  There is a very old and wise saying, "cotton kills" when it comes to damp and cold weather.  Great video.  Thanks

Silk is another natural material to use to help with temperature regulation. Soft to go against your skin. Woven tight enough it can stop wind flow through your clothes. It can also be woven in such a way that it is insulative or thin enough to stay cool in the warm weather. It is an excellent lining material to pair with wool.

In the Canadian army reserves we were taught the acronym COLDE - Clean- Overheating is bad - Loose layers - Dry - Eat. Easy way to remember most of your points - you skipped eat, gotta feed the furnace

An excellent camp shoe when your boots are drying and you know there won't be any goblins attacking anymore are simple wooden clogs! Think dutch clogs, you wear them in camp with some thick socks or felted booties, and the wood insulates sooo good from the cold of the ground. They are rather cheap around 30 bucks, absolutely period and very good to just slip on when going to the bathroom at night. And also very easy to clean and by far the best solution in muddy situations (you can also put shoe nails for better grip).

Also with long hair (specifically with hair to mid-back and lower) braids pinned/tied around your head can create air pockets underneath a hat/hood and help with warmth! (Plus then your hair gets less sweaty and messy.)

For those in dresses: take advantage of split pants as an undergarment. You don't have to fight or fuss with your clothes, you can simply squat over a hole or commode, and if you have a modern toilet you just hike your skirts and sit backwards(good practice for wearing a wedding dress, btw). Women have done it that way for centuries so it must work well!

Viking hood is amazing piece of clothing.
Also, practiced nalbinding and so far I have created few beanies and mittens. Right now making socks. I recommend giving it a try, it's thousands of years old knitting style!

For gloves, I grew up with fingerless mittens. They were basically fingerless gloves, but had a mitten flap buttoned at the tip to the back of your hand. You could unbutton it to pull the pocket over your fingers, or keep it back to use your hands. Quick, effective, and my favorite glove design to this day.

I've also seen fingerless gloves that have a small slit near the fingertip. This allows you to keep the fingers for your glove, but then pull back the tips if you really need to.
Despite their similarities to the fingerless mittens, I wouldn't recommend these ones. You need to wrestle with each and every finger rather than pulling back a single flap. Worse, the tips aren't even big enough to button, so they constantly get in the way.
Not even to mention, they also look very modern.

If you try to wax a cape, make sure you are useing the right kind of wax and that you reserch how it's done first. your not wanting the turn the cape into something like a cardbord statue.

One caveat on wearing fur- while.most times animal pelts were worn with the fur on the outside as decoration instead of protection, some pelts have water resistance due to the layering of the fur and work well as additional barriers against snow or even rain. So while you want fur inverted on the interior layers, caribou, reindeer, and similar fur is also handy as an outer snow barrier wrapped around the outer part of the legs or as a supplementary mantle.

What do you call a Medieval spy?

Sir Veillance.

Don't forget your snowshoes to walk on and not in the snow. They don't weigh much and easy to mount on your backpack. You sweat less, consume fewer calories and your feet stay a lot drier. It is a must have for winter excursions.
(And they look great on your backpack)

Side note from the backpacker side: Backpackers say, "Cotton kills."  Cotton, as you pointed out takes a long time to dry.  If you are in a situation where getting wet can kill you (via hypothermia) it is a very poor choice.  Modern backpackers do use synthetic materials, but they also use wool (alpaca wool is especially nice).

The best advice I've ever received is to learn to be comfortable at lower temperatures (within reason)

I'm finally going to Learn how to be warm!