I want to have late August. My experience was: I started to check from July 24, it only has Tue and Thurs, even for end of july and early August. I continued to check till July 30. It was still that. I do not want to wait and choose Tuesday. Must be in Ritan. If you choose Beijing, it will be all "GREY",i.e. not available. At beginning, you should choose H1b. Then only Ritan is available, but only Tue adn Thurs. Thanks. hope it helps.