The Pacific Typhoon Season, or simply typhoon season, is an event during which a tropical cyclone (TC) forms in the Northwestern Pacific Ocean. The Western North Pacific (WNP) region has TCs that form or track the Northern Marianas, East Asia, and Southeast Asia including the Philippines. On the average, 20 tropical cyclones enter the Philippine Area of Responsibility (PAR) every year, of which 8 or 9 make landfall.
The Philippines only has two main seasons: (1) the wet season which occurs from June to October and (2) the dry season which falls from November to May.
Does this mean there is no typhoon season in the Philippines? Indeed, there is. However, its big difference from the main seasons is that the typhoon season happens all year round, and that a TC can form within PAR any month of the year. A similar scenario happens within the rest of the WNP Basin, with the majority of TCs developing from May to December. This is the practical reason PAGASA does not declare the beginning and end of the typhoon season, if there are any.
P.S. Why is it called #typhoonseason instead of “tropical cyclone season”? The former term originated from the fact that strong TCs in the NW Pacific are called typhoons. Also, the large percentage of TCs in the country reach #typhoon category.