MANILA, Philippines — Sunday, August 23, 2025. The southwest monsoon — widely known in the Philippines as habagat — is forcing heavy rainfall across large parts of Luzon today, raising the risk of flash floods and landslides in Metro Manila and several surrounding regions, according to the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA). The state weather bureau issued its 24-hour public forecast at 5:00 AM this Sunday, valid until 5:00 AM Monday, August 24.
While Luzon bears the brunt of today's wet weather, the rest of the country — the Visayas and Mindanao — will not be completely spared, as scattered showers and isolated thunderstorms are expected to persist driven by the easterlies.
What Is Driving Today's Weather?
The primary weather driver today is the southwest monsoon, or habagat. This is a large-scale seasonal wind pattern that brings warm, moisture-laden air from the South China Sea and the Indian Ocean into the western side of the Philippines from roughly June through September each year. When this monsoon flow is active, it continuously pumps moisture into Luzon's western seaboard, triggering prolonged and sometimes intense rainfall — particularly over Metro Manila, Central Luzon, and the Ilocos coast. Today, PAGASA confirms it is directly affecting Luzon.
Additionally, PAGASA is monitoring three tropical cyclones currently outside the Philippine Area of Responsibility (PAR): Typhoon Saudel, a tropical depression east of Samar, and Tropical Depression Gaenari to the north. Although none of these systems are currently inside PAR, their presence can enhance moisture flow into the country. PAGASA will continue to track them. At this time, no tropical cyclone wind signals are in effect anywhere in the Philippines.
Region-by-Region Forecast
Metro Manila and Key Luzon Regions — Heavy Rain, Flash Flood Risk
The most significant weather impact today will be felt across a wide swath of Luzon. PAGASA specifically identifies the following areas as experiencing cloudy skies with moderate to occasionally heavy rains and thunderstorms, directly caused by the southwest monsoon:
- Metro Manila
- Ilocos Region
- Cordillera Administrative Region (CAR)
- Cagayan Valley
- Central Luzon
- CALABARZON (Cavite, Laguna, Batangas, Rizal, Quezon)
- Mimaropa
- Bicol Region
Residents in these areas face a genuine risk of flash floods and landslides, PAGASA warns. The combination of sustained moderate to heavy rainfall and the potential for thunderstorm bursts means that low-lying communities, riverbanks, and mountainous barangays should remain on alert throughout the day.
Rest of Luzon — Light to Moderate Rains, Thunderstorms Possible
Provinces not specifically listed above but falling within the broader Luzon landmass will see partly cloudy to cloudy skies with light to moderate rains and possible thunderstorms, also driven by the southwest monsoon. Even in these areas, PAGASA notes that flash floods and landslides remain a concern in vulnerable localities.
Visayas and Mindanao — Scattered Showers, Isolated Thunderstorms
Across the Visayas and Mindanao — collectively described by PAGASA as "the rest of the country" — expect partly cloudy to cloudy skies with scattered rain showers and thunderstorms. The driving force here is the easterlies, the trade winds blowing in from the Pacific Ocean on the eastern side of the country. These are generally weaker in their rain-producing capacity compared to the habagat, but they are sufficient to generate localized downpours, especially over mountainous terrain. Flash floods and landslides remain possible in susceptible areas of both island groups.
Wind and Coastal Water Conditions
PAGASA's wind and coastal water forecast paints a challenging picture for maritime activities today, particularly in northern and western Luzon:
- Luzon: Moderate to strong southwest winds. Coastal waters are expected to be rough over the northern and western sections of Luzon, with wave heights reaching levels hazardous to small sea craft.
- Visayas: Moderate to strong southwest winds. Seas described as moderate to rough.
- Mindanao: Light to moderate winds. Coastal waters are slight to moderate — comparatively calmer, though mariners should still exercise caution.
Decoding the Warnings: What Each Level Actually Means
No tropical cyclone wind signals are currently in effect anywhere in the Philippines. However, PAGASA's forecast carries an implicit operational warning through its descriptions of rough seas and the flash flood and landslide risks attached to the heavy rainfall forecast. Understanding how to read PAGASA's weather warnings can help you and your family make better decisions today and in future weather events.
For today's conditions, the key risk language from PAGASA's bulletin is the explicit mention of possible flash floods and landslides accompanying the heavy rain forecast for Metro Manila and the enumerated Luzon regions. This is PAGASA's way of telling residents that rainfall intensity may be sufficient — especially when compounded by existing soil saturation from previous days' habagat rains — to cause rapid flooding in low-lying streets, underpasses, and near waterways, as well as slope failures in hilly and mountainous areas.
The rough seas advisory over northern and western Luzon effectively means that small fishing boats and bancas should not venture out into these waters today. Strong southwest winds will generate wave conditions that are dangerous for vessels without the capacity to handle open-sea swells.
What This Means for You Today
Commuters in Metro Manila and Luzon
Expect wet and potentially disrupted commutes throughout Sunday. Moderate to heavy rain can fall at any time of day, not just in the afternoon. If you must travel, allow extra time and avoid flood-prone underpasses and low-lying roads. Keep emergency contacts handy and follow your local government's flood advisories.
Fisherfolk and Small-Boat Operators
PAGASA's forecast of rough seas along the northern and western seaboards of Luzon is a strong signal to stay ashore today. Moderate to rough seas in the Visayas also warrant caution for small-vessel operators in that region. Only Mindanao's waters are described as comparatively calmer — but even slight to moderate seas can be dangerous for small bancas. Do not take unnecessary risks at sea today.
Farmers
Farmers in Ilocos Region, the Cordillera, Cagayan Valley, Central Luzon, and CALABARZON should be aware that heavy rainfall raises the risk of flooding in low-lying agricultural areas and landslides on sloped farms. Secure equipment and livestock where possible. In Visayas and Mindanao, scattered rains could bring beneficial moisture but watch for localized flooding in flat, low-lying farm areas.
Students, Parents, and Schools
Sunday is generally a rest day for most schools, but for any weekend classes, tutorials, or activities planned in Metro Manila and the affected Luzon regions, parents should monitor the situation closely. Rain may intensify without warning, and children should not be outdoors during thunderstorms. If classes are scheduled for Monday, August 24, keep an eye on local government announcements, as the habagat may persist.
Outdoor Workers and Construction Crews
Those working outdoors in Luzon — particularly in construction, infrastructure, and agricultural settings — face the highest personal risk today. Heavy rain combined with thunderstorms creates hazardous conditions. Seek shelter immediately during lightning activity and avoid working near slopes or riverbanks where landslide risk is elevated.
Temperature Outlook
PAGASA's observed data for the previous day in Manila recorded a maximum temperature of 30.5°C and a minimum of 27.5°C, with a relative humidity ranging between 64% and 100%. Under today's cloudy and rainy skies driven by the habagat, temperatures across Metro Manila and the rain-affected parts of Luzon are expected to remain on the cooler, more overcast side. In the Visayas and Mindanao, where cloud cover is less uniform, temperatures may be somewhat higher during breaks in the rain.
"Cloudy skies with moderate to occasionally heavy rains and thunderstorms are expected [in Metro Manila and listed Luzon regions]... Possible flash floods or landslides during severe thunderstorms." — PAGASA, 24-Hour Public Weather Forecast, 5:00 AM, August 23, 2025
Bottom Line
If you are in Metro Manila or anywhere across Luzon today, prepare for moderate to heavy rain and stay away from flood-prone areas and coastal waters. The southwest monsoon is fueling persistent, potentially heavy rainfall that brings a real risk of flash floods and landslides — not just in the mountains, but in urban areas too. Residents in the Visayas and Mindanao should stay alert to localized showers and thunderstorms. Today is not the day for sea travel in northern and western Luzon.
Monitor official PAGASA updates at pagasa.dost.gov.ph.