How could a move after I use foresight ever miss?

Question

I battle with scyther in fog and it always use double team until it evasion won't go higher. First, I use foresight, and then hypnosis...but, IT MISS! can someone tell me why?

Answer 1

There are two reasons why this happens:

-Hypnosis, in Generation IV, only has about 60 accuracy.
-Fog lowers accuracy passively, by one stage.

So Hypnosis, even after using Foresight, probably was only about a 50/50 chance in terms of accuracy.