I went this year at the end February for five weeks and it was great, holidays had finished so most of the tourist were gone and it was just me and the locals and the odd tourist. The water and wind was excellent it blew every day(20-40knots) that i was there, i took one day of because the smallest sail i had was a 4.7 and the wind was way to strong even for that. Coronations was good but got quite busy at times, and unless you are a confident jumper it might prove somewhat of a challenge...if you don't jump yet you will be by the time you get back. I spent most of my time in Geraldton itself sailing St Georges beach and Sunset beach, these were excellent spots for the intermediate sailor. St Georges for is flat water bump and jump, just watch out for the crayfish pots the ropes will pull you up pretty quick and Sunset for it beginner wave sailing. The caravan park at sunset beach backs right onto the water, just rig up carry your gear 15m and your in the water. I also stayed in a cottage($400 p/w for the cottage way cheaper then the caravan park) at Pt Moore for a few weeks, Pt Moore has pretty good sailing just watch out for the kiters and stay away from Hells Gates. The locals were all friendly offering lots of advice, tips and hospitality i would suggest you go and see Rik at Sailwest for all the info on local spots.
This will be the best holiday you will have in Australia...Well it was for me anyway, I'll be back again in Feb 2010....Here is a pic of Coronations in its glory.