Why Sudden Afternoon Rains Are Happening More Often, According to PAGASA

(SPOT.ph) The weather has been giving mixed signals lately: hot and humid in the morning, then suddenly gray and rainy by late afternoon. Does that mean the dry season is finally over?

According to the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA), not officially—at least not yet. PAGASA Weather Specialist Benison Estareja said the Philippines is currently in the transition period between the dry and wet seasons.

“Kasalukuyan nasa transition period po tayo o panahon sa pagitan ng tag-init o dry season at tag-ulan o wet season. Patungo na po tayo sa wet season, at isa sa mga senyales nito ay ang mas madalas na pag-iral ng thunderstorms, lalo na sa hapon hanggang gabi,” Estareja said in a weather forecast.

One sign of that transition is the more frequent occurrence of thunderstorms, especially in the afternoon and evening. This is exactly what we're experiencing in Luzon right now.

But afternoon rain does not automatically mean the rainy season has started. PAGASA usually links the rainy season to the onset of the southwest monsoon, or habagat, which brings warm, moist winds and rain over the western portion of the country. Based on PAGASA’s latest climate outlook, the climatological onset of the southwest monsoon might fall between May 16 and June 15.

At the same time, the heat isn't letting up just yet. PAGASA Weather Specialist Chenel Dominguez said the heat index in Metro Manila may still reach 39°C to 41°C, so it's best to avoid going out in the afternoon, when the heat is at its peak. If you really have to step out, bring some cover—yes, the same umbrella you’ll probably need for the rain later.

Also read: PAGASA Releases 2026 Typhoon Names in the Philippines

According to PAGASA, the declaration of the rainy season requires two specific criteria: (1) there has to be rainfall for five straight days, with each day recording at least 25 millimeters at seven out of the 13 monitoring stations across Luzon and Visayas and (2) there has to be a shift in the dominant wind direction where prevailing winds should come from the west (south-southwest, southwest, west-southwest, west, west-northwest). That shift signals the arrival of habagat.

As of now, none of these has happened yet.

For now, PAGASA is expecting one or two tropical cyclones in May and another one or two in June. Across the May-to-October forecast period, the agency said 9 to 17 tropical cyclones may develop or enter the Philippine Area of Responsibility (PAR).

Also read: Why Does PAGASA Name Typhoons After People?