The Pacific Ocean is a very active basin for the development of intense storms. Moreover, the Western Pacific Ocean sees even more storms in terms of both number and frequency. These storms that occur in the Western Pacific Ocean affect the Southeast Asian countries as that is the closest landmass to this part of the ocean.
The waters in the Pacific Ocean are warmer as compared to other oceans. In fact, the Western Pacific Ocean is warmer than the Eastern Pacific Ocean which is why the former hosts more storms in comparison to the latter.
The vertical wind sheer is also conducive for storm formation and intensification in the Pacific Ocean as compared to the Atlantic Ocean. These storms of the Western Pacific Ocean have a relationship with the Indian seas. In fact, some of them even enter the Indian seas as weaker weather systems and affect the coastal parts.