Can you double layer socks?
As a result, double-layer socks can be a much better option for blister prevention than single-layer socks. They're especially useful for activities where you'll generate more friction and sweat, such as hiking and jogging.
Many people think that wearing layering or thick socks is the best solution for dealing with cold feet. But they actually create pressure on your feet and cut off blood circulation to your toes. So in order to keep your feet warm and dry, you need socks that are breathable, moisture-wicking and thin or medium-thick.
Bring an extra pair of thick socks that you can wear at night while your others dry. The thin sock will dry quickly so you only really need one pair. Advantages: less blisters, drier feet, less pain.
Double-layer socks can prevent blisters by reducing friction and wicking away moisture. 4 Some double layer socks, such as WrightSocks, even come with a no-blister guarantee. You can also wear two pairs of socks, which is a common tactic for hikers.
If You're Trying to Stay Warm, One Pair is Plenty
“Your boots were designed to hold your feet and one pair of socks, not two,” he explains. “The second pair compresses your foot, cutting off circulation and making your feet colder than they'd be with a single pair.
Two Socks Worn Together
You can commonly see basketball players of all ages wearing two pairs of long socks during a game or practice. The double-layer helps eliminate friction between your foot, the shoe and the ankle brace.
Less Friction Between Sock & Shoe
Wearing two socks will make for a tighter fit for the shoe, causing the foot to be locked in place with the shoe.
Poor blood flow (circulation) in your legs and feet causes cold feet. Poor blood flow means that it takes longer for the blood to reach your feet. Your blood travels through pathways (blood vessels) in your circulatory system. These pathways can close, harden and narrow, making it difficult for blood to flow steadily.
Thin socks dry more quickly than thicker socks, wicking moisture away from your skin and keeping you comfortable. This decreases the risk of developing blisters on your feet. If you have tight spots in your shoes caused by wearing thick socks, you may experience health problems due to restricted blood flow.
Wearing socks all of the time is generally regarded as perfectly healthy if done properly. There are myths that wearing socks 24/7 can lead to fungal growth and result in foul smelling feet. If changed regularly, there should be no health problems associated with wearing fresh socks all day and night.
Can too many socks make feet cold?
Bulky, ill-fitting socks tend to bunch and actually inhibit circulation to feet, which is key. A liner + wool sock is great, but doubling up on thick socks or layering cotton + wool actually can make your feet colder.
A Guide To Socks & How To Style Them - YouTube

I would recommend wearing the thermals over underwear especially since you probably want to wear them a few days without washing :-) Socks go over the thermals to help keep snow out. Generally you probably want to max out at three layers - a thermal layer, a light ski top or fleece and then a ski jacket.
Wear a Double Layer of Socks
1 This works well for keeping your toes warmer for winter walking. But don't choose a combo that ends up too thick to wear with your shoes. SmartWool socks are a good choice for the wool layer as they are less scratchy and are machine-washable.
To avoid cold feet one can wear a thin pair of "wicking" liner socks next to the skin and a heavier pair atop them. The liner socks remove perspiration that helps cause cold feet and quickly transfers it to the heavier outer socks.