How do I find out what the framerate is?

Is there some kind of framerate variable I can use extensively throughout thousands of objects? What about time.deltaTime? Would that be able to represent actual framerate?

I'm kind of trying to control a chain reaction by deleting branches based on whether the fps drops below 60.

They are mostly controlled now, but I have this feeling there is still a freak chance that I might have an atomic bomb waiting inside of my project that would bring any computer to a dead stop. It would also be cool because then even slow computers wouldn't go out of control with the special FX.