If you are serious about racing cyclocross this fall/ winter and want to maximise your potential, now is the time to start planning! You need to give yourself 4 to 6 months to fully prepare if this is your focus. If you've been training and racing all year then you'll have a good foundation and need less time to prepare. If you want to be a cyclocross specialist and eschew the other disciplines of bicycle racing, time to get going!
Roadies and Mountain Bike racers keep your seasons in mind too. Give yourself six months of training before your A priority events next year. You need to be considering next year around October/ November of this year. A ton of improvement can take place in six months, but you can't make much headway if you only get serious a few weeks or a month out. Planning and preparation is the key to success!