In reply to trish1968:
If that walk appeals, if you're not going climbing, more detail: We caught the MTR to Hang Hau, then bus to Sai Kung, then another bus to Pak Tam Au in Sai Kung Country Park East. From there it was a 5.8 mile sweaty hike via Sharp Peak to the beaches at Ham Tin, where there were welcome cafes, shade and cold drinks. The speed boat ride back to Sai Kung was terrific fun, and very scenic, and Sai Kung itself was very interesting, with lots of local fishermen selling their catches along the pier.
The buses and trains are frequent and cheap.
I did it in April and could barely walk another step when I got to the beaches. Which of the heat, the humidity or the jet lag contributed most to that I don't know, but I guess it is even hotter now! Take loads of water.