The summer monsoon in the South China Sea has changed significantly over the past 51 years. In the mid-1970s, there was a noticeable shift in the onset dates and intensities of the monsoon. Before 1975, the monsoon activity was not linked to sea surface temperatures in tropical oceans, but after 1975, warmer waters in the Indian and Pacific Oceans started affecting the monsoon. This change is believed to be connected to the long-term variations in ocean temperatures.