The Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) reported that Guiuan, Eastern Samar experienced a 51-degree Celsius (°C) heat index on Saturday, May 18.
This heat index is only 1°C below the "extreme danger" category and just 2°C short of matching the all-time high of 53°C recorded in Iba, Zambales.
PAGASA reported that Sangley Point, Cavite recorded a heat index of 47°C, followed by Dagupan City, Pangasinan, and Roxas City, Capiz at 46°C.
The heat index reached 45°C in Iloilo City, Iloilo, and 44°C in Bacnotan, La Union; Iba, Zambales; Cuyo, Palawan; Dumangas, Iloilo; Catbalogan, Samar; Dipolog, Zamboanga del Norte; and Zamboanga City, Zamboanga del Sur.
A heat index of 43°C was logged at Ninoy Aquino International Airport (NAIA) in Pasay City, Metro Manila; Laoag City, Ilocos Norte; Casiguran, Aurora; Cubi Pt., Subic Bay, Olongapo City; Ambulong, Tanauan, Batangas; Coron, Palawan; San Jose, Occidental Mindoro; Puerto Princesa City, Palawan; Legazpi City, Albay; Virac (Synop), Catanduanes; Masbate City, Masbate; and Catarman, Northern Samar.
Meanwhile, it reached 42°C in Science Garden, Quezon City, Metro
Manila; MMSU, Batac, Ilocos Norte; CLSU, Muñoz, Nueva Ecija; Alabat, Quezon; Calapan, Oriental Mindoro; Juban, Sorsogon; Siquijor, Siquijor; and Tacloban City, Leyte.
On May 18, 32 areas reached the "danger" heat index.