I've seen clouds forming throughout the day, and then watch them drift away in the late afternoon. After sunset I see lightning downwind where the clouds have gone.
Yep. We can draw lines on a map for our information, but the information they give is that there is some sort of boundary between two climate types.
That's definitely true, but when you have the Great Dividing Range between you and the ocean, not much moist air gets over those ranges. Even the eatward moving remnants of the tropical air masses coming from the Indian Ocean sweem to pass to the north along the Queensland border.