how cold does it usually get in oklahoma during the winter?

You won't likely see any days over 70 during those months in Oklahoma and most temperatures will be closer to freezing, on average.

here are the stats for Oklahoma City:

http://www.usclimatedata.com/climate/oklahoma-city...

It depends on the year, honestly. Most of the time it's going to be between 30 and 60 degrees. That being said, I've seen -20 degree weather in January and 3 weeks later it was 80 degrees. Pack so you can dress in layers. You'll want warm weather clothes (not hot), cooler weather clothes, and cold weather clothes as well as a heavy coat.

It can be very cold in Oklahoma, and below freezing with a strong North wind.

Get some warm clothes.

parts of Oklahoma bitter cold.