Nine areas across the country are expected to experience dangerous level heat indexes on Saturday, according to the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA).

Dagupan City’s heat index is expected to reach 45°C based on the forecast of PAGASA.

Meanwhile, the following areas were expected to experience heat indexes ranging from 42°C to 44°C:

Dagupan City, Pangasinan: 45°C

Aparri, Cagayan: 44°C

Laoag City, Ilocos Norte: 42°C

Tuguegarao City, Cagayan: 42°C

Puerto Princesa City, Palawan: 42°C

Aborlan, Palawan: 42°C

Masbate City, Masbate: 42°C

CBSUA-Pili, Camarines Sur: 42°C

Catarman, Northern Samar: 42°C

PAGASA considers a heat index reaching 42°C to 51°C as "dangerous."

According to the state weather bureau, heat index refers to the so-called “init factor” and to the apparent heat felt by a person when high air temperatures are combined with humidity.

The weather bureau said that danger level heat index may cause heat cramps, exhaustion, and heat stroke with continued exposure to the sun.

To prevent heat-related illnesses, PAGASA encouraged the public to limit their time spent outdoors, drink plenty of water, avoid tea, coffee, soda, and liquor, wear umbrellas, hats, and sleeved clothing outdoors, and schedule heavy-duty activities for the beginning or end of the day when it is cooler.

PAGASA formally declared the beginning of the dry season on 23 March.