What is the right dress to wear to Sydney, Australia in early September? thank you

September is spring in China and autumn in Sydney. There is not much difference. It doesn't matter how you dress in China or Sydney.

Australia is warm all the year round, except for two weeks in winter (but not less than 5). It won't be too hot in summer, except for 1 week, where the temperature will continue to be high (above 40). For most of the year, the climate is quite pleasant and people can wear beautiful clothes. Bring more clothes for spring, summer and autumn.