During Late Triassic-Early Jurassic, the Junggar basin was in a warm and wet climate due to the effect of continental monsoonal climate. From middle to late Jurassic, the climate shifted as a seasonal arid climate that initiated from the northeast and then widespread to the whole basin. This is because the Pangea started to break apart that halted the effect from the mega-monsoon system. Therefore, the basin became affected by westerlies. The westerlies contained the lesser moisture that has come from the northwest since the marine areas gradually minimized to the recent Caspian Sea. With the continuous uplift along the Tian Shan, the orographic effect around the basin intensifies the rain-shadow effect. The prominent rain-shadow effect results in a warmer seasonal arid climate in the basin. At the same time, the lakes in the basin had higher salinity and lower sedimentation influx.