I grew up in Iowa, lived there from the day I was born until I started college. I have since lived in South Dakota and now Minnesota. The weather in January can be a toss up. Most likely it will be in the teens with snow on the ground, it could be a beautiful upper 30s and sunny, or it could be -30 windchill and dang near deadly out with blowing snow. Our idea of cold is probably different than your idea of cold, but you can still have a good time.
I've hunted in a lot of extreme weather, and often times they can produce good hunting. Some tips for January hunting... have 4 wheel drive on your vehicle. If the road or access looks too deep in snow, then it probably is, don't test it. Bring a shovel. Cell phone with battery and reception. Dress in layers, it's easier to take layers off then add layers on that you don't have with you. But don't dress too warm that you can sweat a lot, once that sweat dries you'll be miserable. If you stay dry, you can manage about anything. Last year, final day of the season in Minnesota was around a -30 wind chill, I wore ski goggles while hunting! There was no way in hell I could have stayed out with any part of my skin exposed, especially with the cold wind whipping at my face/eyes.
If there is too much snow on the ground, I would probably cancel the trip. Walking several miles in a couple feet of snow is not fun nor easy. I have worn snow shoes while pheasant hunting before in a few feet, and while they do help, they are also a pain at times while going through brush.
A lot of the cover will be snow covered, which is both good and bad. The good, there is less cover to search, when you find one bird, you will probably find several birds. The bad, when one bird flushes, you may also stand there watching every bird in the entire county flushing at the same time just out of range.
If you are coming that far, I'm guessing you will have a dog you're bringing with? If so, be smart with the dog but often times they are tougher than we give them credit for. I have a lab that you can just tell loves the cold weather, so I don't have much to worry about. However, a different breed that is not used to the cold, may have some struggles?
The best kind of flushes are roosters bursting our of some cover in the snow, it's a sight to see! My best advice, is just keep an eye on the weather and snow that Iowa is receiving.
Lastly, while you've come this far in January, stick around for (what I'm guessing would be your first time) some ice fishing! I'm sure somebody on here ice fishes and would take you out for a day if you post on here enough.