The rainy season is about to start in the Philippines as manifested by the isolated afternoon or evening rain showers and severe thunderstorms, said the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) on Wednesday, May 26.

PAGASA's Climate Monitoring and Prediction Section chief Ana Liza Solis said the frequent occurrence of sudden but brief heavy rains and severe thunderstorms in the afternoon or evening means that the country is already in a climate transition period from dry season to wet season.

"Malapit na po. Yung inoobserbahan po nating wind ay nagsa-south, southwest, south-southwesterly wind flow na sya at sinasabi rin sa international prediction centers na maaga po ang onset ng Indian summer monsoon o yung northern hemisphere summer monsoon (The onset of rainy season is near. The wind we are observing is now south, southwest, south-southwesterly wind flow. The international prediction centers are also seeing an early onset of the Indian summer monsoon or the northern hemisphere summer monsoon)," Solis said during a virtual climate outlook forum on Wednesday.

"Yun po yung minomonitor natin pero hindi pa rin yung prevailing southwest monsoon ang nakikita nating hangin. So it's just around the corner. Pati rin po sa distribution ng ulan. Maybe first week of June, basta first half of June posible po nating maranasan (That's what we're monitoring but we still don't see the prevailing southwest monsoon. So it's just around the corner. As well as the distribution of rain. Maybe by the first week of June, up to the first half of June we can experience the start of rainy season)," she added.

In 2020, PAGASA declared the onset of rainy season on June 12.

Solis said PAGASA is currently monitoring a low pressure area (LPA) east of Mindanao that could trigger the onset of the southwest monsoon or "habagat."

"Historically nakikita po natin ang onset ng southwest monsoon it could be triggered by a low pressure area or bagyo (we have observed that the onset of the southwest monsoon could be triggered by a low pressure area or cyclone)," she explained.

However, Solis said dry periods also known as a "monsoon break" may still occur during the rainy season.

"Posibleng maranasan pa rin po yung mas matataas or medyo maiinit na temperatura at alinsangan dito sa Metro Manila at karatig na lugar pagdating po ng June. Although sinasabi nga natin na magkakaroon na ng onset ng rainy season may mga tinatawag din po tayong monsoon break (It is possible that we will still experience slightly warmer temperatures and higher humidity here in Metro Manila and neighboring areas by June)," Solis explained.

"Dun sa mga monsoon break kapag tag-ulan ay medyo makakaranas pa rin po tayo ng tinatawag na lull na posibleng medyo mas mainit ang temperature natin at mataas yung ating heat index pero hindi na kasing init ng naranasan noong second week hanggang third week ng May na napakataas ng alisangan natin (During a monsoon break, we will experience a lull in the rain wherein we may experience slightly warmer temperature and higher heat index. But it will not be as hot as what we experienced in the second week to the third week of May)," she added.