I've planned to hong kong by end of august. Is it good time to walk around or is it cold wind?

It is not cold, but quite hot. The temperature will range from 79F to 88F. However, you need to pay much attention to the typhoon because August is the rainy season in this area. The weather conditions would influence the sightseeing a lot.
So you are suggested to change the travel plan. November to May next year is regarded as the best time. :)

Tq very much. Appreciated.😊