Only the Kimberleys has serious monsoonal weather at that time of year. Parts of the inland Pilbara eg Karijini have occasional afternoon rainstorms but most of it happens in Jan to March. Cyclones have been known in October but are rarely seen. Northern parts are getting quite hot in October but anywhere south of Exmouth is still quite comfortable. Getting far enough south to avoid the heat would be my concern.
We have been in Broome in early October and actually really enjoyed it, it was fairly hot in the days, great for the beach and pool, but the nights were still reasonable and it was fine for early morning walks. We intentionally sat out the WA school holidays in Broome because where we wanted to go further south to Karijini or Ningaloo reef is absolutely packed and booked out during those couple of weeks. Broome at that time still had quite a few tourists and things like the Horizontal Falls trips were still operating, but the biggest crowds were gone. We do like warm weather and found it a fairly ideal time, you would want to be south of there by late October though as it warms up further and gets more humid with hotter nights. Really depends on the type of weather you like.
We went through WA /NT back down centre . Started end of Feb from Penrith . Adelaide, Perth taking our time around coast to Broom . Btw its NOT a Sunday drive lol ., May June July seems the best months up north., The centre was nice and cool when sun went down . I keep an eye on weather forecast latter in season . Being we dont have travel or time limit . Our theory is road was flooded ?? We would stop for a few days .. Didnt happen !
-- Edited by Aus-Kiwi on Wednesday 27th of December 2017 10:07:31 AM
We worked for a while in Pilbara area - south of Port Hedland. Got really hot in October - by end of month was 40+ outside. November saw lots of massive thunderstorms with strong winds and there were also regular strong willy willys - strong enough to affect a vehicle driving on road.
My experience is that it can be unpleasantly hot around Karratha by start of October.
So I would be advising to be south of that area by then.