At least for the Western Australia end I would be very much factoring in the wind ... Perth and the south-west of WA is known for being windy. We even have infamous winds, the
Fremantle Doctor and the Albany Doctor [not so famous as to get is own wikipedia page
] [1] are two that come to mind.
Anyway for information on winds I suggest you refer to the
BOM wind roses and for temperature data see
http://www.bom.gov.au/climate/data/[1] I can recall many an evening when I lived in the wheatbelt sitting outside supping on a beer, to hear a roar coming across the paddocks to moments later have anything blown all over the place and grabbing a jumper. That was the Albany Doctor. A blessing on a hot evening, not such a blessing if you had to ride into it
.
You also need to consider that WA and the Nullabor are pretty flat so the wind tends to have free range across the paddocks and of course on the Nullabor a southerly is coming from Antarctic straight across the ocean into your face
My regular summer commute is south in the afternoon; 42 km of coastal riding into the Fremantle Doctor. Riding daily into a wind over summer which commonly blows at 40 km/h plus is not fun.
Personally I would be checking those roses