Extreme temperature events commonly known as heat waves (HWs) have profound impacts on human health and natural systems. Under ‘global warming’, the frequency and magnitude of HWs have increased over recent decades, and are projected to intensify in the future, exerting increasingly impacts on society in many parts of the world. An improved scientific understanding of this phenomenon is important for the planning of mitigating measures that are aimed at alleviating its adverse effects. In this project, we have conducted a systematic investigation of the HW behaviors in China at various time scales from days to decades. In particular, their synoptic behavior and physical causes, interannual variations and the linkage with the zonal and meridional modes in the tropical Pacific ocean (i.e., El Niño Southern Oscillation and Pacific meridional mode), long-term trends and the impacts of regional urbanization. In addition, we have also examined the behaviors of human-perceived heat stress that describes the combined effect of high temperatures and humidity.