Is there a particular season that is better for a new rider to start? And a particular season that horses may be a little more antsy-say, depending on the breeding cycle?

Most horses aren't that flighty unless they are bred repetitively and then skip a season or a stallion (neither type a beginner should be riding anyway ;) ). Beginner's horses should be bomb proof, but the most comfortable time to start riding is probably spring or summer when less clothing is necessary. Long sleeves and pants are still recommended but a heavy jacket and thermals won't be needed and that way the rider's position can be see more clearly.

I agree with purplefdu. Summer is the best season I find because I live in a mild climate and so the temperature is nice. It is not to hot an uncomfortable. To me comfort is one of the most important thing when learning to ride.

I started riding in the fall, but we have mild winters here and it hasn't been a problem all winter. Probably depends on where you live.

I would start in the early summer. Here, our winters are quite cold and I find horses get a little stir crazy. In the early spring they tend to be quite full of energy. By early summer they settle down a fair bit.

I would have to agree with early summer. Let the horses get the spring joy out of their systems before starting, we all get a little stir crazy over the winter with all the time indoors.

l agree with what other people have said. But anything thing to consider too is that during the late spring and summer it is more of the show season. So depending on the barn the trainers may be gone pretty often. But i would say starting early fall or late summer is a good time to start riding.