There were a couple of days in July that actually reached a higher temperature (27°), but this particular night in August the temperature stayed high throughout the evening also. I recall driving late at night with the top down, almost committing the unforgiveable sin of whining about hot weather in Norway(!). Back home, even later at night, I checked the temperature which hovered around 24°. Quite unusual, the city was bustling with people until early morning hours.
If the temperature stays above 20° throughout the night it is defined as a "tropical night" (at least in Scandinavia), doesn't happen too often.
I see you're Australian by the way, I spent a some years in Queensland and I suspect my time there made me too soft for the winter here..