I have to drive a long ways to squirrel hunt so I leave early and hunt from dawn until I get tired. I usually will hunt resident geese the same morning so I may start out with a 22 and go back to the truck and get the 12 guage if the geese are in the river. I do not normally hunt them until late winter.
I will usually walk a long and watch for them on the ground. If I get to a den tree that I know is active I will sit and wait for about 20-30 minutes and then move on.
I nearly always shoot using a tree as a side rest.
The main thing about the weather is that the squirrels will hole up on the very cold days for two to three days before coming back out.
If I see five squirrels I might get three, although I have seen five often enough and gotten none of them. Seldom will I get all of them. Mostly, if they get in a hole I will just move and not try to wait them out. Squirrels only get away because they outrun me on the ground or they get to a hole.
I use a stock 10-22 with only a few mods such as a magazine release and some smoothing on the sears, wierd bedding of the action and grinding off the front sight. It has a Burris 3X9 scope and a stock pad to get a better cheekweld. I have heard lots of people brag about how their bone stock 10-22 shoots great one hole groups but that is not my gun.