Cairns is trans-seasonal.
What you should wear, is something you would wear on a pleasant summer's day.
It will get cooler at night but not by much, you can easily go without a jumper or wrap or jacket
If it rains, it's not like normal rain, often it's a light drizzle which will dry up very quickly if you get wet you won't get cold and you'll be dry in no time.
Sunglasses are optional, coming from Perth originally I would never walk out the door without a pair but here if you forget them you would probably be ok.
Amateurs Racing Carnival should be a dry heat but if it's humid for any reason be prepared for thigh perspiration.
Avoid it by using special chafing powder or if you're lucky enough to have a thigh gap or small bust it won't be an issue.
Sunscreen is a must, humidity will make your hair frizzy and makeup run so take a small makeup supply.
Some ladies prefer fascinators to a hat you're more likely to perspire wearing a hat though it does give you more sun coverage.
Three quarter or short sleeve, flowy dresses are ideal to wear. FOTF events usually have knee or lower hem lengths and not too much skin showing.
A great way of getting around this, if you have a strapless dress wear a sheer blouse underneath.
Being in the tropics bright colours work very well on stage and in our surroundings.
Comfortable shoes are ideal but not necessary there are plenty of chairs to sit on and lots of shaded areas to take refuge.
Its a quick 8 minute taxi ride from the city centre and you will be dropped right out side of the gates.