Why do storms form even during the dry season?

A tropical cyclone spotted outside the Philippine Area of Responsibility (PAR) may intensify into a super typhoon despite the prevailing hot weather, according to PAGASA.

The development highlights a recurring question: why do storms form during the dry season?

Data from PAGASA show that tropical cyclone activity typically peaks from July to September, with an average of three storms per month. Still, cyclones can develop at any time of the year in the Philippines.

In April, the average drops to just 0.5 storm, making such occurrences relatively rare but not unusual. Over the past 80 years, 39 tropical cyclones have entered the PAR during the month.

PAGASA weather specialist Robert Badrina said this pattern is linked to the ocean’s high heat capacity, meaning seawater takes time to warm up and cool down.

From February to April, ocean temperatures are still gradually increasing following the winter season in the northern hemisphere, limiting storm formation.

For a tropical cyclone to develop, several conditions must be present. Sea surface temperatures must reach at least 26.5°C to 27°C at a depth of about 46 meters, allowing moisture to evaporate and rise into the atmosphere, forming clouds and a low-pressure system.

As pressure at the center drops, winds intensify and begin to rotate, eventually developing into a storm.

A large body of water, such as the Pacific Ocean, is also needed to sustain and strengthen cyclones. This explains why fewer storms form on the western side of the Philippines, where the surrounding seas are smaller.

Another key factor is the Coriolis force, generated by the Earth’s rotation, which enables storms to spin and organize.

Given these conditions, PAGASA said storms can form regardless of the season, underscoring the need for year-round preparedness among Filipinos.—Data from GMA News Feed/MCG, GMA News