Green’s Dictionary of Slang

(Aus./N.Z.) the rainy season.

1894		G. Boothby On the Wallaby 159: Cairns has but two seasons, the wet and dry, or, in other words, the rainy and the fine.
1908		J. Gunn We of the Never-Never (1962) 3: No woman travels during the Wet.
1932		I.L. Idriess Flynn of the Inland 236: The old box of tricks would get through somehow and chug into Canarvon triumphantly ahead of the next ‘wet.’.
1948		S.L. Elliott Rusty Bugles II v: Frig the rain . . . belt the rain . . . you beaut. Here it comes . . . the great big Wet.
1958		W.E. Harney Content to Lie in the Sun 203: When the ‘wet’ is over, I too will go on my walkabout.
1964		T. Ronan Packhorse and Pearling Boat 155: It was a reasonably cool, end-of-the-wet morning.
1971		P. Bodeker Sandgropers’ Trail 11: We close the dry winter season for our six months’ fishing because summer up north is ‘the wet.’.
1987		B. Chatwin Songlines 50: Roe River [...] could be cut off by the ‘wets’ for three months or more.
1996		Penguin Bk of More Aus. Jokes 460: An intrepid Englishman [...] booked himself a cycling holiday in outback Queensland during the big wet.
2003		McGill Reed Dict. of N.Z. Sl.