The northeast monsoon or "amihan" will bring rains across Northern Luzon on Friday, the weather bureau said.
Light rains will prevail over Batanes and Babuyan Islands, while isolated light rains will be experienced across Ilocos Norte, Apayao, and Mainland Cagayan.
Meanwhile, Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) forecaster Veronica Torres said the prevailing easterlies cause fair weather in Metro Manila and the rest of the country.
She said thunderstorms are also likely, and severe thunderstorms could result in flash floods or landslides.
A temperature of up to 33 °C is forecast in Zamboanga.
The temperature in Metro Manila, Legazpi, Laoag, Kalayaan Islands, Puerto Princesa, Iloilo, Tacloban and Davao could reach up to 32 °C.
Torres said the highest forecast heat index is 42°C in Coron Palawan.
Moderate winds and moderate seas will prevail throughout Northern Luzon.
Elsewhere, winds will be light to moderate with slight to moderate coastal waters.
No low pressure area is being monitored for possible tropical cyclone formation, PAGASA said. (PNA)