Being a native Minnesotan, I used to spend a lot of time sitting out on the frozen lakes, ice fishing. (I have since wised up and now spend my winters in AZ). kevinweitzel75 hit the nail on the head when recommending warm socks. Layering
is as important to cold weather footwear as to the rest of your upper clothing.
A thin, non-absorbing, sock should be worn next to the skin to allow perspiration to pass through to a bulky outer layer(s). Beyond that, the boot can be of a medium weight with a windproof outer shell but able to accommodate a good quality felt liner. If it's going to be wet, then the boot should be waterproof, if not, keep the boot only as heavy (and bulky) as you want to pack. The boot size should be a minimum of one size larger than your normal shoe size to accommodate the additional socks without compressing the stocking material.
I found a hiking sock called "Smart Wool" that has good bulk yet does not (resists) compress. This stocking works really good for hiking, but has been a preferred footwear during the cold snaps too.
Enjoy your stargazing
On every trip into the Superstitions, I find another Gold Mine. Today the mine was filled with Memories. I can not wait for the next trip.