My recollection is that manufacturers will start to publicize the new bikes towards the end of July, right around the end of the Tour de France. Bikes will hit stores a few months later.

The annual refresh is a crapshoot. Some colors get better, some worse. Sometimes parts get better, sometimes they'll downgrade the frame or the wheels....

Waiting is also crapshoot. They might not have your size, you might not get a big discount.

I'd just say if you need the bike and you like what you see, you might as well do it. If you don't need it and you're on the fence about color and parts, then wait.