So this semester I’ve been out of school for nearly a month, due to traveling (for academic things), AP tests (5 days), and being sick for a few days. As a result, my final grades are pretty low:
AP Physics B-
AP Macro A-
English B
AP Stats B
Gym A
That results in a 3.267 GPA for my second semester of Senior year, would Grinnell rescind my offer?
No. If you haven’t failed or gotten Cs in anything, you should be fine.
I sure hope so, thanks! This semester was just absolutely crazy… I’d catch up on something, then I’d have to be out of school for the next few days… Felt like I was playing catch-up the entire semester 
It is very rare for Grinnell to rescind admission. You’d have to drop well into C or D averages for this to even slightly become a concern. You are not in that range at all it seems.
The only significant thing that may happen from your grades is your first year tutorial adviser may ask you about what happened – especially if say your all other semesters of high school saw A’s in all your science classes. This happened to me because I had a C+ on my transcript for my junior year in AP chemistry. It’s by no means a “red” flag, but something that your adviser at grinnell will have genuine curiosity over.
Take the first year at grinnell to show you can do well in college and the rest of your high school transcript will no longer matter.
Good luck.
Oh okay, thanks guys! : )