Because of WA's
magnetic latitude, which around 44S from memory, it only sees aurora during big events. Tasmania and NZ see them more regularly as they are a lot closer to the south magnetic pole.
You need to watch the
Kp index (which is currently at a storm level of 6 as a write!) which I access from the
Spaceweather page and when that to gets to 6 and above you know you're in with a chance. I think rogerg has photographed a very faint one from Lake Leschenaultia at Level 5, but you wouldn't see it visually at that level in Perth, that's a pretty good indication of what usually happens from Perth and southern WA. Sometimes only the camera can see them, they're just not bright enough for the eye, but a long exposure picks up enough light to detect them.
A lot of us also subscribe to the
ips email alert system, which is govt run. This is usually good for giving a heads up for possible aurora and you at least know you should be keeping an eye on the indices when you get them.
But generally unless its a big storm (Kp index 6 or more), like the one just past over 16-18th March, you wont see much from Perth.
Hope that helps.
