February is midsummer. Bring your shorts, swimmers, bathers, togs, whatever your local words are. Hat is a must. Wide brim. I have a collection of Panama style. My wife insists on a new one at start of summer.
Tintaldra has summarised Melbourne nicely. All over Australia the best parts are outside the big cities.
From my experience Sydney is comparable to August in Hamilton, Bermuda and I would speculate by extension, Charlston.
Cairns comparable to August in George Town, Cayman Islands and Kingston, Jamaca. Though have only spent a week or so at a time in each. Cairns in February is subject to quickly developing cyclones. Good insurance would be prudent.
A/C. Al fresco is my preferred dining. At waterfront/beach settings seems pointless wasting what nature has provided. Open air beer gardens are nice too. Cannot recall the last time I had a summer evening meal in an A/C place.
At a guess mall, shopping centres set the temperature around 22c.
Hope it helps a little.