My sister has lived in Cairns for nearly 20 years. Her house is not a Queenslander, but one of the modern concrete boxes (with an irregular shape), on the side of a hill so it has a lower level for garage and a bedroom. When they moved in there was no a/c, only ceiling fans. As the years have passed and she and hubby get older, more rooms have had a/c added (split unit reverse cycle heat pump style, not central). The wet season, our summer, is diabolical as far as humidity goes. Temps around 30 degrees with high 90s humidity for weeks on end, and lots of drizzly rain outside. My mother (in her 80s) usually goes to stay with her during the winter but has to come home again in October before the temp and humidity starts rising to uncomfortable levels.
As others have said, it does get cyclones there (hurricanes in North American terms) Nothing as devastating as Cyclone Tracey in Darwin in 1974, but non-trivial damage can occur.
If you live a bit further from the coast, Kuranda is nice but small and it’s up a hill so benefits from lower temps. Also Mareeba which is inland a bit further again and at 400 odd metres. It still has a tropical feel with maximum temps up to 38 degrees in January but can actually get close to frosts sometimes during the winter.
The Great Barrier Reef extends for 1200 km along the Australian east coast and there are many tours available from Cairns or Port Douglas to various parts of the reef off shore. That and the rain forest in the area are the main attractions for tourists. Ocean swimming is something I am reluctant to take part in from the mainland. There are warning signs at all main beaches about sharks, crocodiles and stingers. They’re enough to put me off. However, diving or snorkelling out on the reef is great. Too far out for most crocs and the stingers hug the shoreline. Only the possibility of sharks to worry about.
If you want to visit, go during the dry season, April through to October. November starts to get too hot and also starts to get wet and the humidity rises. Cyclone season is also November through to May.
Cairns is relatively isolated from the rest of Australia too. Its about 350km south to Townsville, the next major city. North, there’s virtually nothing past Cooktown which is 330km from Cairns. West, there’s a whole lot of nothing for hundreds of kms to the Gulf of Carpentaria for more nothing. (There are a few towns out there but their total population would only be between 1 and 2 thousand people.)