I think hawks are most active in the fall. They can see so much better from sky to ground with leaves off the trees. Hawk loss reports on BYC are highest in the fall.
I don't know about other predators....like owls, coons, coyote, etc....
I only see racoons in my yard Spring and Summer. It is the time they are raising babies.They don't seem to be around when the weather is cold. I have a feeling they are around all the time, just don't see them.
I have an eagle that flies over in the Summer, but don't see it other times of the year.
I'm pretty sure all predators needs to eat year round, so I'm glad they stay away from my chickens.