For each 1◦C increase in during GPw, yield increased for winter wheat in Zone I, Zone II and Zone V of northern China by 9.4%, 1.7% and 0.7%, respectively (Fig. 4). By contrast, yield decreased for winter wheat in Zone III and Zone VIII of southern China by 3.1% and 2.3%, respectively (Fig. 4); as well as for spring wheat in Zone IV and Zone VI of northwestern China by 1.3% and 6.1%, respectively.