A performance evaluation of two passive cooling strategies is presented: daytime ventilation and night cooling, for a six storey apartment building in Beijing and Shanghai, China. A coupled, transient simulation approach is used in order to model heat transfer and air flow. CFD is used to simulate wind-driven ventilation, and Fanger's comfort model is used for occupant thermal comfort. States that the results indicate the superiority of night cooling over daytime ventilation, although there is a high condensation risk. For Shanghai neither were found to be suitable.