Yes, the sale season has started already. You'd better book a hotel in advance it is the tour season.
In summer, frequent thunderstorms are the norm. Average temperature is 28C (82.4F). Bring an umbrella and dress lightly in cotton.

Thanks for the reply. Where can I buy cheap yet good quality clothes for guys? And also electronics as well? What is the percentage discount for usual stores like Giordano, Bossini or Esprit; and would the discounting get higher by the end of August? Thank you in advannce.

Every July and August is the summer promotion in Hong Kong. You could find these summer clothes, such as I.T. and Esprit, at every reasonable price. Well, it is difficult to say the percentage since the discount may different in different store. You could visit Harbour City, Sogo, CityGate Outlet and Elements for shopping.