G'day mate, just leave them uncovered, they will be fine, they have been surviving for Millenia without help and a few rainy days will not hurt them. As long as the sun still comes up and goes to bed as usual, the plants will not flower early just because it is cloudy. It takes surprisingly little light to "activate" your plants into day mode and clouds still let a lot of light through that your plants will still register that it is daytime and not be freaked out that autumn has arrived early. Outdoors, it takes quite a few days in a row that are getting shorter and the dark nights of the new moon, to initiate flowering, so a few less sunny days right now will be no problem. Up until the summer solstice, December 21, the days are still getting longer and your plants will "know" this too, so they will also "know" now is not the time for flowering. I would only cover them with something if hail was forecast, but I doubt there will be any hail where you are or anywhere near Brisvegas way. In fact covering them with a tarp could induce fungal or mould problems due to reduced air flow and extra heat. She'll be right. Just let nature do her thing.
Hope this helps.... Organoman.
If you have any other "Aussie questions", just message me through the comments in one of my diaries and I will try and give you "Aussie" specific answers. Cheers!