The rainy season has begun a few days ahead of its usual schedule in late May, the Philippine Atmospheric, Geophysical and Astronomical Services (Pagasa) said Wednesday.

“The presence of frontal system and the occurrence of severe thunderstorms have brought widespread rains during the last five days in areas under Type I climate and other parts of the country,” Pagasa administrator Vicente Malano said in its website.

“Moreover, southwesterly windflow was also observed during the past few days. This satisfies the criteria of the start of the rainy season over the western sections of Luzon and Visayas,” he added.

Metro Manila and other western parts of the country are expected to start having intermittent rains linked to the southwest monsoon, but there will also be rainfall breaks, he said.

It added that the La Nina weather phenomenon will continue to affect some parts of the Philippines, which would make heavy rains likely in the following months.

''During the last five years, the rainy season starts in the fourth week of May or first week of June,'' said Senior Weather Specialist Rusy Abastillas in a phone interview with the Daily Manila Shimbun.

The peak of the southwest monsoon is usually from June to August, “but if we start from the onset, it will waive by September,” added Abastillas.

She said the country expect eight to 12 tropical cyclones from June to September. Based on historical track, Northern Luzon is usually region most affected by the storms, she said.

Abastillas said the country is headed towards the southwest monsoon which will last until September. Jaspearl Tan/DMS