Published May 17, 2026 7:59pm + Add GMA on Google Make this your preferred source to get more updates from this publisher on Google. More than 30 areas across the country are expected to experience “danger”-level heat index on Monday, May 18, the state weather bureau said.Based on the five-day heat index forecast of the Philippine Atmospheric, Geophysical and Astronomical Services Administration, at least 35 areas may record heat index levels ranging from 42°C to 45°C.Areas under the “danger” category are expected to register the following heat index levels:45°CCoron, Palawan San Jose, Occidental Mindoro Cuyo, Palawan 44°CDagupan City, Pangasinan Sangley Point, Cavite City, Cavite Roxas City, Capiz 43°CLaoag City, Ilocos Norte Baler (Radar), Aurora San Ildefonso, Bulacan Hacienda Luisita, Tarlac City Ambulong, Tanauan, Batangas Puerto Princesa City, Palawan Borongan, Eastern Samar Guiuan, Eastern Samar Dipolog, Zamboanga del Norte Zamboanga City, Zamboanga del Sur Butuan City, Agusan del Norte 42°CNAIA Pasay City, Metro Manila Sinait, Ilocos Sur Aparri, Cagayan Tuguegarao City, Cagayan Casiguran, Aurora Iba, Zambales CLSU Muñoz, Nueva Ecija Cubi Pt., Subic Bay, Olongapo City Infanta, Quezon Alabat, Quezon Mulanay, Quezon NAS-UPLB, Los Baños, Laguna CBSUA-Pili, Camarines Sur Iloilo City, Iloilo Dumangas, Iloilo La Granja, La Carlota, Negros Occidental Catarman, Northern Samar Catbalogan, Western Samar Tacloban City, Leyte Maasin, Southern Leyte Meanwhile, more than 30 areas are forecast to experience “extreme caution” heat index levels ranging from 33°C to 41°C.Only Itbayat, Batanes is expected to fall under the “caution” category with a projected heat index of 31°C.Areas forecast to record “not hazardous” heat index levels, or below 27°C, include Baguio at 26°C, Benguet State University in La Trinidad, Benguet at 24°C, and the Benguet radar station in Tuba at 19°C.PAGASA said the heat index refers to the temperature the human body feels when relative humidity is combined with actual air temperature. High humidity reduces the evaporation of sweat, making it more difficult for the body to cool down. —MCG, GMA News