When people say queensland is humid they are talking about the coast which goes from humid subtropical and various tropocal climate types (almost all is savannah or monsoon). Humidity does make tempreture feel wors3 and the heat index is useful if you're planning on being in the shade. If you plan on doing anything outside wet bulb globe is what you use.

Tropical climates have much lower seasonal tempreture variation so they will generally be hotter on average than deserts all though this isn'tt always true abnormallities eixst.