I have a tub of Quaker’s Oats in my dorm room, and I will be gone for the next five weeks. It’s about 3/4 of the way filled. I don’t want to bring it with me. Should I throw it out, or will it be okay by the end of January?
I should think it will be fine, really. Anyway, why would you have to decide now? You can leave it until you come back, and then decide. If it’s in a reasonable container, I can’t see why there should be problems. I’m a little bit amused by the fact that your weeks away might well involve eating all sorts of celebratory food, and you are worried about your sad little stash of oatmeal at home. I know the feeling! It’s always good to know there is an emergency food supply. 
You should be fine. Oatmeal last a while as long as it stays dry. In a dorm room over break, when they probably turn the heat off anyway, there shouldn’t be a problem. But, as Celyn says, decide when you get back.
Oatmeal stored properly lasts a long time. According to this site it has a 12-month shelf life.
It’s also one of the foods used by survivalists, backpackers, etc. who need foods that will last.
Barring a bug infestation or excessive moisture, five weeks should not be a problem.
The good folks at Quaker Oats said this to me on the phone today…
“Technically Quaker Oatmeal is good for 12 months after the expiration date. However, it can last years longer than that (indefinitely?) if you put it a plastic bag, wrap that in foil and put it in the freezer”
Just put it into something insect proof. Finding that spider-webby stuff in the can AFTER I’ve poured some into boiling water is one of my least favorite things.
I store mine in the freezer, but I’ve got lots of room.