Manila, March 3 -- State weather bureau Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) has yet to declare the onset of summer but "danger" heat indexes are already being recorded.

PAGASA recorded 42 degrees Celsius heat index in Echague, Isabela on Sunday.

On Monday, PAGASA stations in Munoz, Nueva Ecija forecast 45 degrees; and Science Garden, Quezon City and Clark Airport, Pampanga 46 degrees.

As of posting time, the city governments of Valenzuela, Caloocan, Malabon and Las Pinas in the National Capital Region have already declared suspension of face-to-face (F2F) classes on Monday.

Caloocan City's shift to asynchronous classes or blended learning will be for Kinder to Senior High School in pub...