Despite the presence of severe tropical storm Aghon in the country, the municipality of Guiuan in Eastern Samar recorded on Sunday the highest heat index so far this year.

The weather bureau, PAGASA, recorded the locality's ‘init' factor hitting 55 ºC, which is considered to be under the category of extreme danger heat index.

On 28 April this year, the highest dangerous heat index of 53 °C was recorded in Iba, Zambales.

Under this classification, a heat stroke is imminent, said PAGASA.

On the same day, Metro Manila had its hottest temperature in history—38.8 °C, recorded at the Ninoy Aquino International Airport in Pasay City.

The effect-based danger classification effects on the body are that heat cramps and exhaustion are likely, and heat stroke is probable with continued exposure.

The heat index is the human discomfort index that is identified into four effect-based classifications: caution (27°C to 32°C), extreme caution (33°C to 41°C), danger (42°C to 51°C), and extreme danger (52°C and beyond).

With the rainy season nearing its possible onset in June, a lower ‘init factor’ may be expected in Metro Manila in the coming weeks.

Heat index forecast

As of 26 May at 5:00 p.m., a forecast from PAGASA showed that 32 areas were seen to have a dangerous heat index on Tuesday.

Guiuan in Easter Samar remains to have the estimated hottest temperature of 47 °C.

Meanwhile, 45 °C is predicted in Zamboanga City, Zamboanga Del Sur, and Tuguegarao City in Cagayan, Virac (Synop) in Catanduanes, Catarman in Northern Samar, Tacloban City in Leyte, Borongan in Eastern Samar, Laguindingan Airport, Misamis Oriental, Surigao City in Surigao Del Norte with 44 °C.

Aparri in Cagayan, ISU in Echague in Isabela, Puerto Princesa City in Palawan, Masbate City in Masbate, Catbalogan in Samar, Maasin, Southern Leyte, and Dipolog in Zamboanga Del Norte, on the other hand, are forecast to have their temperatures reaching the highest at 43°C. Lastly, a temperature of 42°C is expected to prevail over Laoag City, Locos Norte, Dagupan City, Pangasinan, and MMSU in Batac. locos Norte, Bacnotan in La Union, NVSU Bayombong in Nueva Vizcaya, Baler (Radar) and Casiguran in Aurora, Daet in Camarines Norte, Legazpi City in ALbay, Roxas City in Capiz, Iloilo City in Iloilo, Dumaguete City in Negros Oriental, Pangalo International Airport in Bohol, Siquijor in Siquijor, Davao City in Davao del Sur, and Butuan City, Agusan Del Norte.