The wind you have is a bigger factor than most places. I bought my first "mountain" tent after western Oklahoma winds broke a couple of decent tents down. A tent not built for that will drive you nuts with flapping and with wind blowing through the tent under the fly. A lot of backpacking tents have mostly mesh bodies. That's not good in high winds.
Don't forget to buy some better stakes. Most backpacking tents come with stakes that just won't hold in high wind. Sure, they'll hold in gusts, but our constant wind will "work" stakes loose over time.
Good advice is to get a really warm bag and don't skimp on the sleeping pad. I use two pads, one an inexpensive ridge rest and then a warm foam pad.
If you are going to use a cot, you'll want a bigger tent. I'll warn you that setting up a big tent in high winds can be a real pain. For a smaller dome tent, say 4 person or less, I've found a candle lantern to do a good job of knocking the chill off in weather hanging around the freezing mark.
