On August 14, what season is it in Sydney, Australia (Latitude 35° South) ?

Winter

Its ending of winter in August in Sydney.

Explanation:

Australia is one of the 7 continents that is present in earth. It's located in Southern hemisphere. So due to the revolution of earth, when northern hemisphere comes closer to sun, southern hemisphere goes away and vice versa. So when it's summer in northern hemisphere, it's winter in Southern hemisphere.

In August, in Northern hemisphere, the summer ends and winter starts setting in. Thus in Southern hemisphere, or in Sydney, there's ending of winter and the starting of summer there.