The Philippine Atmospheric, Geophysical, and Astronomical Services Administration (PAGASA) said the highest recorded heat index on Monday, April 1, was 45°C in Dagupan City, Pangasinan.
PAGASA has classified this heat index as "dangerous."
Eight other areas in the country recorded dangerous heat indices on Monday.
The second highest heat index was 44°C, recorded at the Central Bicol State University of Agriculture (CBSUA) station in Pili, Camarines Sur, and at the PAGASA station in Roxas City, Capiz.
Meanwhile, a heat index of 43°C was recorded in Dumangas, Iloilo, Catarman, Northern Samar, and Aborlan, Palawan.
Moreover, a heat index of 42°C was felt in Baler, Aurora, Iloilo City, Iloilo, and Cotabato City, Maguindanao.
Based on the PAGASA's daily heat index report, the highest recorded temperature this year was 48°C on March 27 in Roxas City, Capiz.
PAGASA considers a heat index of 42 to 51°C to be dangerous, as it can lead to heat stroke, heat cramps, and heat stroke from continued activity.