visiting Hong Kong around 22-24th August. What will the weather be like during this period and is it a good time for a family holiday?

It will be hot and a little wet then, with the average temperature of 31C. Thuderstorm or shower may happen from time to time. As it will be during the typhoon season, you need to check the weather forecast in advance.

Actrually, Oct. to Apr. in the next year shall be the best travel season in HK.