Will visit Hangzhou on 10th to 30th August. what will be weather?

The temperature during that period of time is 68 F to 95 F. And it mainly contains cloudy days. The climate is quite warm. Short sleeves, skirts and other summer clothes are enough for you to prepare. :-)

Unbearably hot and humid, it's a sauna in August. Wear as little as possible, and bring plenty of drinks if you go hiking etc. It's a little better if you are in a forest, but in the city not only is it unbearably hot and humid, there is often not even a light breeze to help. The humidity makes it feel much hotter, that is a really key factor that is not mentioned here.