THE state-run weather bureau on Monday warned of much hotter days ahead and heat indexes at extremely dangerous levels that would last until the second week of May.

Aside from the dry season, the soaring temperatures and heat indexes are being triggered by the El Niño phenomenon, although this has started to weaken, said weather specialist John Manalo of the Philippine Atmospheric, Geophysical and Astronomical Services Administration (Pagasa).

Citing records, he said at least 36 key areas, including Metro Manila, have already been experiencing "dangerous" heat indexes ranging from 42 degrees Celsius to 51 degrees Celsius.

"We could expect that the number of affected areas across the country would go higher as these hotter weather and higher heat indexes would be more evident until the second week of May," he said in an interview on PTV-4.

People escape the unbearable summer heat by staying inside a mall in Antipolo City on Monday, April 29, 2024. PHOTOS BY JOHN ORVEN VERDOTE People escape the unbearable summer heat by staying inside a mall in Antipolo City on Monday, April 29, 2024. PHOTOS BY JOHN ORVEN VERDOTE People escape the unbearable summer heat by staying inside a mall in Antipolo City on Monday, April 29, 2024. PHOTOS BY JOHN ORVEN VERDOTE

The highest heat index so far that was recorded was 53 C in Iba, Zambales, on April 28, the Pagasa forecaster said.

Manalo said Metro Manila registered a record-breaking heat index on April 27.

The heat index is what the temperature feels to the human body when relative humidity is combined with the air temperature.

Heat indexes from 41 to 51 C are considered to be at a dangerous level, where heat cramps and heat exhaustion are likely. Continued exposure could also cause heat stroke, Pagasa said.

Heat indexes from 52 C are considered extremely dangerous.

Manalo said the public must limit the time spent outdoors, especially from 10 a.m. to 4 p.m.; drink plenty of water; avoid coffee, tea, soda and liquor; use umbrellas; wear hats and sleeved clothing outdoors; and schedule heavy-duty activities for the beginning or end of the day when it is cooler.

By June, he said there would be a transition to a neutral weather system and eventually to the onset of La Niña, where sea surface temperatures in the western Pacific are warmer than normal, bringing more rainfall and severe floods.

The state-run weather agency has predicted, however, that there could be a delay in the start of the rainy season, which could take place in the second week of June.

At a briefing in the House of Representatives, Jorybell Masallo, officer in charge of the farm weather services section of Pagasa, said El Niño will stop, but its impact will continue to be felt up to the second or third quarter this year.

Masallo said advisories had been issued to agricultural areas that there was a 60 percent chance there would be a La Niña phenomenon in June, July or August.