QUEZON CITY, September 10, 2026 — The southwest monsoon is making its presence felt across wide swaths of the Philippines on Thursday, bringing heavy rain to parts of Luzon, triggering flash flood and landslide watches, and spreading cloudy, rainy conditions as far as the Visayas and portions of Mindanao, according to the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA).
PAGASA issued its 24-hour public weather forecast at 4:00 AM on Thursday, September 10, 2026, valid until 4:00 AM on Friday, September 11. The agency has placed Zambales under heightened watch for flash floods and landslides due to direct monsoon rain, while a broad stretch of Luzon — from Metro Manila to highland Cordillera provinces — faces the same risks from occasional to heavy rainfall.
What Is Driving This Weather?
The culprit is the habagat, or southwest monsoon — a seasonal wind system that draws warm, moisture-laden air from the South China Sea and the southwest Pacific toward the Philippine landmass. When this flow is active and strong, it collides with the country's mountain ranges and forces moist air upward, wringing out heavy rain, particularly over windward western slopes and lowland areas that lie in its direct path. According to PAGASA, the southwest monsoon is currently affecting Central Luzon, Southern Luzon, and the Visayas — making those regions the most directly exposed to its effects today.
This is a well-understood seasonal pattern, but it is one that demands respect: when the habagat is sustained and the rains accumulate over hours, rivers rise quickly, slopes saturate, and flash floods can develop with little warning — particularly in provinces like Zambales, which bear the full brunt of westward-facing monsoon flow.
Luzon: The Hardest-Hit Region Today
Zambales — Highest Risk
PAGASA singles out Zambales as the area most exposed to monsoon rains today. Residents face the most direct threat of flash floods and landslides. Those living near rivers, creeks, or hillside communities should remain on heightened alert and be prepared to evacuate if local authorities issue the call.
Metro Manila and Surrounding Provinces
Metro Manila, together with the rest of Central Luzon, Pangasinan, La Union, Benguet, Isabela, Nueva Vizcaya, Quirino, Rizal, Cavite, Batangas, Oriental Mindoro, and Occidental Mindoro, can expect occasional rain driven by the southwest monsoon. PAGASA warns that moderate to heavy bursts within this rainfall are enough to trigger flash floods and landslides, particularly in low-lying urban areas and mountainous terrain. The Cordillera provinces of Benguet, and highland provinces like Nueva Vizcaya and Quirino, are especially susceptible to landslides when sustained rain saturates their steep slopes.
For Metro Manila commuters, expect wet roads, reduced visibility during heavy spells, and the possibility of localized flooding in flood-prone streets and underpasses — particularly during peak rush hours if rain intensifies.
Rest of Luzon
Areas of Luzon not specifically named above will also experience cloudy skies with rain and thunderstorms, also attributed to the southwest monsoon. Flash floods and landslides remain possible due to moderate to heavy rains. Residents across the Luzon island group should treat Thursday as a day to stay weather-aware, regardless of their specific province.
Visayas and Parts of Mindanao: Rain and Thunderstorms
The Visayas region, along with Zamboanga Peninsula and nearby parts of Mindanao, will see cloudy skies with rain and embedded thunderstorms — all driven by the southwest monsoon. While PAGASA's language for this area is slightly less urgent than for Central Luzon and Zambales, the flash flood and landslide threat from moderate to heavy rains remains active here as well. Residents and local government units in these areas should not treat Thursday as an ordinary rainy day.
Mindanao: Localized but Still Dangerous Thunderstorms
The rest of Mindanao — areas beyond the Zamboanga Peninsula and monsoon-directly-affected zones — will experience partly cloudy to cloudy skies with localized thunderstorms. PAGASA attributes these to localized thunderstorm activity rather than the monsoon itself. Even so, the agency flags the risk of flash floods and landslides from these storms, which can dump intense but geographically concentrated bursts of rain in short periods. Mindanao residents should not dismiss localized thunderstorms as minor — these can be fast-moving and dangerous in vulnerable communities.
Coastal Waters and Wind Conditions
Winds across the country are expected to be light to moderate, coming predominantly from the southwest — consistent with active monsoon flow. Coastal water conditions are classified as slight to moderate nationwide, with wave heights reaching 0.6 to 1.8 meters.
- Northern Luzon: Light to moderate winds; slight to moderate seas
- Visayas and rest of Luzon: Light to moderate southwest winds; slight to moderate coastal waters
- Mindanao: Light to moderate south to southwest winds; slight to moderate seas
Wave heights of up to 1.8 meters can pose a serious hazard for small, motorized watercraft. Fisherfolk and small-boat operators should verify sea conditions with their local coast guard station before departing, and avoid areas where conditions may deteriorate.
Understanding Today's Weather Hazards
PAGASA has flagged flash flood and landslide risks across multiple regions today. These are not abstract threats — they are the documented consequences of the rain intensities the agency is forecasting. To understand how to read PAGASA's weather warnings — including what rainfall color-coded alerts mean and when they require action — consult our full explainer.
In practical terms: when PAGASA warns of possible flash floods due to moderate to heavy rain, it means that rivers and drainage systems in affected areas could overflow faster than expected. Low-lying communities, areas near rivers and esteros, and those at the base of slopes should be the first to prepare an evacuation plan and identify their nearest evacuation center.
What This Means for You Today
Commuters (Metro Manila and Luzon Urban Areas)
Allow extra travel time on Thursday morning and afternoon. Heavy rain spells can reduce road visibility and cause rapid flooding in low-lying intersections, underpasses, and flood-prone barangays. If your usual route passes through a flood-prone area, identify an alternate path in advance. Avoid wading through floodwater of unknown depth.
Fisherfolk and Small-Boat Operators
Wave heights of up to 1.8 meters are forecast for coastal waters nationwide. This is within the range that can swamp or capsize small, open fishing boats. Exercise caution, check with local maritime authorities before heading out, and do not attempt to ride out worsening conditions at sea. Safety ashore is the priority today.
Farmers
Those in Zambales, Central Luzon, and the Cordillera highlands face the greatest risk of crop damage from intense rain, flooding, and potential landslides affecting farm roads and irrigation infrastructure. Secure loose equipment, check drainage channels, and postpone any farm activities that require outdoor work in exposed, elevated, or flood-prone areas.
Students, Parents, and School Administrators
Parents and school administrators in Zambales, Metro Manila, Central Luzon, and other rain-affected areas should monitor local government announcements regarding class suspensions. PAGASA's forecast of moderate to heavy rain with flash flood risk is the kind of condition that can prompt Local Chief Executives to call for suspensions — particularly in provinces already under heightened alert. Keep updated through official local government social media channels and radio stations.
Outdoor Workers and Construction Sites
Workers in exposed outdoor environments — construction sites, agricultural fields, mountainside roads — should have a clear plan for seeking shelter if rain intensifies. In hilly or mountainous areas, be alert for signs of slope instability: fresh cracks in the ground, unusual sounds, or water seeping from hillsides. Do not shelter beneath trees or unstable structures during thunderstorms.
Temperature and Humidity Outlook
PAGASA's weather station at Science Garden in Diliman, Quezon City recorded the following figures for the 24-hour period ending at 8:00 PM on Wednesday, September 9:
- Maximum temperature: 33.7°C (recorded at 2:00 PM)
- Minimum temperature: 24.7°C (recorded at 6:00 AM)
- Maximum relative humidity: 97% (recorded at 8:00 AM)
- Minimum relative humidity: 66% (recorded at 3:00 PM)
The near-maximum humidity reading of 97% in the morning reflects just how saturated the atmosphere has become under monsoon conditions. High humidity combined with warm temperatures means that even periods between rain spells may feel oppressively muggy. Stay hydrated and avoid prolonged outdoor exertion during the warmest parts of the day.
Bottom Line
The most important thing you can do today: if you live in or near a low-lying, flood-prone, or mountainside community in Zambales, Central Luzon, Metro Manila, or the Visayas, do not wait for floodwater to reach your door before acting. Know your evacuation route, monitor your local government's official announcements, and take PAGASA's flash flood and landslide warnings seriously — the habagat is strong, the atmosphere is saturated, and conditions can deteriorate quickly. When in doubt, move to higher ground early.
Monitor official PAGASA updates at pagasa.dost.gov.ph.