The municipality of Pili in Camarines Sur is predicted on Friday to have the highest 'init factor' in the Philippines, peaking at 48°C, while some 39 areas are seen to have a dangerous heat index swinging between 42°C and 51°C.

The latest report from the Philippine Atmospheric, Geophysical, and Astronomical Services Administration (PAGASA) shows that the cities of Dagupan in Pangasinan and Tacloban in Leyte are predicted to have an 'init factor' of 46°C and a scorching 45°C in Bacnotan in La Union, Puerto Princesa City and Aborlan in Palawan, Roxas City in Capiz, and Iloilo City and Dumagas in Iloilo.

Meanwhile, 44°C may likely hit six areas: Laoag City in Ilocos Norte, Aparri in Cagayan, Casiguran in Aurora, Coron in Palawan, San Jose in Occidental Mindoro, and Catarman in Northern Samar.

43°C is also predicted to prevail in Ninoy Aquino International Airport (NAIA) in Pasay City, Sinait in Ilocos Sur, Tugegaro City in Cagayan, Isabela State University in Echague, Isabela, Iba in Zambales, Baler (Radar) in Aurora, Cubi Point in Subic Bay, Legazpi City in Albay, Virac (Synop) in Catanduanes, Masbate City in Masbate, Mambusao in Capiz, La Granja in La Carlota Negros Occidental, and Catbalogan in Samar.

Science Garden in Quezon City, Mariano Marcos State University in Batac Ilocos Norte, Clark Airport in Pampanga, Central Luzon State University in Muñoz, Nueva Ecija, Sangley Point in Cavite, Ambulong in Tanauan Batnagas, Alabat in Quezon, Calapan in Oriental Mindoro, Daet in Camarines Norte, Guiuan in Eastern Samar, Maasin in Southern Leyte, and Zamboanga City in Zamboanga del Sur, on the other hand, are estimated to have their temperatures kick the highest at 42°C.

Baguio City and Benguet State University in La Trinidad remain to have the lowest forecasted heat index at 29°C.

The heat index is the human discomfort index that gives the "apparent" temperature, or what humans perceive or feel as the temperature affecting their body, as defined by PAGASA, which has four effect-based classifications: caution (27°C to 32°C), extreme caution (33°C to 41°C), danger (42°C to 51°C), and extreme danger (52°C and beyond).

On Wednesday, Pili Mayor Thomas Bongalonta Jr. disclosed that three residents of his province have died due to the extreme heat, with one having a heart attack.

With this, he said that they have implemented the suspension of onsite classes in all schools, except for private ones with air-conditioned rooms.

As an intervention, Bongalonta said that his town has a 24/7 pharmacy and on-call doctors in case of emergencies, adding that cash assistance was also extended to persons with disabilities, senior citizens, and solo parents to support their needs.

In April, the highest heat index so far this year was recorded in Iba, Zambales, with its temperature climaxing at 53°C.

Likewise, Metro Manila had its hottest temperature in history at 38.8°C recorded in NAIA in Pasay, surpassing the previous record of 38.6°C registered on 17 May 1915, in Port Area, Manila.

The weather state bureau recently said that a higher heat index may be expected this month.