China's National Climate Center announced that the 2026 South China Sea summer monsoon has fully set in during June, with an intensity ranging from near-normal to above normal.

The onset of the South China Sea summer monsoon marks the arrival of moist tropical airflows over the South China Sea. At the same time, the western Pacific subtropical high weakens and retreats eastward, while southwesterly winds become dominant across the region.

The strengthening influx of warm and humid tropical and subtropical air is expected to significantly enhance convective activity, leading to increased rainfall in southern China and other affected areas. The monsoon rain belt will then gradually move northward from southern China, signaling the start of the country's main flood season.

Also known as the South China Sea monsoon, the weather system is a key component of the Asian monsoon system. It refers to the prevailing southwesterly winds in the lower troposphere over the South China Sea from May to October.

The onset of the monsoon is also regarded as a sign that China's winter monsoon has ended and the summer monsoon season has begun.