Manila — The Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) reported that 13 areas across the country registered “danger” level heat indices on Sunday, April 26, with temperatures reaching up to 45°C, while 10 more areas are expected to experience similar conditions on Monday, April 27.

PAGASA’s 5 p.m. monitoring showed the highest heat index on Sunday was recorded in Dumangas, Iloilo and Guiuan, Eastern Samar at 45°C. Under PAGASA’s classification, a heat index between 42°C and 51°C falls under the “danger” category, where heat cramps and heat exhaustion are likely, and prolonged exposure may lead to heat stroke.

Other areas that reached the danger threshold on Sunday included Sangley Point in Cavite City at 44°C, Cuyo in Palawan at 44°C, San Ildefonso in Bulacan at 43°C, San Jose in Occidental Mindoro at 43°C, Iloilo City at 43°C, La Granja in La Carlota City, Negros Occidental at 43°C, Baler and Casiguran in Aurora at 42°C, Iba in Zambales at 42°C, Puerto Princesa City in Palawan at 42°C, Roxas City in Capiz at 42°C, and Zamboanga City at 42°C.

In Metro Manila, the heat index reached 41°C at NAIA in Pasay City and 40°C at the Science Garden in Quezon City, both under the “extreme caution” category. PAGASA explained that the heat index refers to how hot it actually feels to the human body when air temperature is combined with relative humidity. High humidity slows the evaporation of sweat, making it harder for the body to cool down.

For Monday, April 27, PAGASA forecast that 10 areas will again experience “danger” level heat indices, with values ranging from 42°C to 45°C. The state weather bureau continues to advise the public to limit outdoor activities, drink plenty of water, and avoid strenuous physical exertion during peak afternoon hours. “Heat exhaustion is likely, and prolonged exposure may lead to heat stroke,” PAGASA warned.

The extreme heat has also raised concerns over water supply and power demand. Local governments in highly urbanized areas such as Bacolod City have begun contingency measures, including water rationing, as production capacity has dropped due to the prolonged hot weather.

PAGASA emphasized that heat index values can rise by as much as 9°C when exposed directly to sunlight, making shaded or indoor areas safer during peak hours. The agency urged residents to monitor daily forecasts and take preventive measures to avoid heat-related illnesses.

With temperatures expected to remain high in the coming days, health officials are reminding the public to stay hydrated, wear light clothing, and seek immediate medical attention if symptoms of heat exhaustion or heat stroke occur.