August is the fourth and final peak month. The pattern is unchanged from July, so what decides between them is not the surf: the Southern Ocean is still sending south-west groundswell with period, and the offshores are still holding the point open.
What August adds is the end of it. The lows begin tracking south again towards the end of the month, and September is a different kind of month. The water is at 17°C for a third month, and the air starts turning towards spring. If your dates are flexible inside the winter, the difference between June, July and August is mostly how many people are already there.
