The Philippine Atmospheric, Geophysical, and Astronomical Services Administration (PAGASA) reported that on Friday, May 17, the intense heat reached a "dangerous" level in 35 areas.

PAGASA said Dagupan City, Pangasinan; Roxas City, Capiz; and Catarman, Northern Samar, recorded the highest heat index of the day at 47 degrees Celsius (°C). This was followed by Laoag City, Ilocos Norte; Aparri, Cagayan; Dumangas, Iloilo; and Mambusao, Capiz, at 45°C.
The heat index peaked at 44°C at Ninoy Aquino International Airport (NAIA); Bacnotan, La Union; CLSU Muñoz, Nueva Ecija; Casiguran, Aurora; Ambulong, Tanauan Batangas; Alabat, Quezon; San Jose, Occidental Mindoro; Cuyo, Palawan; Iloilo City, Iloilo; and Dipolog, Zamboanga Del Norte.
In addition, a heat index of 43°C was recorded in Iba, Zambales; Baler (Radar), Aurora; Cubi Pt., Subic Bay Olongapo City; Sangley Point, Cavite; Aborlan, Palawan; Daet, Camarines Norte; Virac (Synop), Catanduanes; Juban, Sorsogon; Catbalogan, Samar; Zamboanga City, Zamboanga Del Sur; and Butuan City, Agusan Del Norte.

Meanwhile, the heat index reached 42°C in MMSU, Batac, Ilocos Norte; Infanta, Quezon; Puerto Princesa City, Palawan; Legazpi City, Albay; Masbate City, Masbate; Guiuan, Eastern Samar; and Cotabato City, Maguindanao.
PAGASA warned that heat indices between 42 degrees Celsius (°C) and 51°C indicate a "danger" level, where heat cramps and heat exhaustion are likely, and heat stroke is probable.
The heat index measures how hot it feels when relative humidity is combined with the actual air temperature.
READ:
https://mb.com.ph/2024/3/18/heat-index-what-is-it-and-how-does-it-differ-from-actual-temperature