QUEZON CITY, August 26, 2026 — The Southwest Monsoon is tightening its grip on Luzon this Wednesday, August 26, 2026, pushing moderate to heavy rainfall into northern and western provinces and raising the threat of flash floods and landslides in vulnerable communities. The rest of the Philippines will remain largely drier but not entirely free of risk, as localized thunderstorms could still trigger sudden flooding in low-lying areas nationwide. These are the findings of the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) in its 4:00 AM forecast bulletin, valid until 4:00 AM on Thursday, August 27, 2026.
What Is Driving Today's Weather
The weather system responsible for today's conditions is the Southwest Monsoon, known locally as "habagat." This is a large-scale seasonal wind pattern in which moisture-laden air flows from the southwest across the South China Sea and into the western side of the Philippine landmass. Because it carries warm, humid air that has traveled over open water, it is capable of producing persistent and sometimes intense rainfall — particularly over western-facing coastlines and mountain slopes where the wind is forced upward, cools, and condenses into rain. PAGASA confirms the Southwest Monsoon is currently affecting Luzon, making it the primary driver of today's rainfall and rough seas.
Region-by-Region Forecast
Northern and Western Luzon: Heaviest Rain
The provinces most directly exposed to the Southwest Monsoon today are Ilocos Norte, Ilocos Sur, La Union, and Pangasinan. PAGASA warns these areas of moderate to heavy rainfall, with the direct consequence being a real and elevated risk of flash floods and landslides. These are provinces where mountainous terrain meets the western coast — exactly the conditions that amplify monsoon rainfall. Residents in low-lying barangays and communities near rivers or slopes should remain on alert throughout the day.
Zambales is also under the monsoon's influence, with occasional rains expected. While the forecast is lighter here than in the provinces to the north, the public should remain watchful as conditions can change quickly.
Metro Manila and the Rest of Central and Southern Luzon
A broad swath of Luzon will experience cloudy skies with scattered rains and thunderstorms that could turn heavy at times. This covers Metro Manila, the Ilocos Region, the Cordillera Administrative Region (CAR), Cagayan Valley, the remaining provinces of Central Luzon, Cavite, Batangas, Rizal, Occidental Mindoro, Palawan, and — crossing into the Visayas — Antique. All of these areas carry a risk of flash floods and landslides during periods of heavy rain, according to PAGASA.
For Metro Manila residents in particular, expect an unsettled day with periods of rain and possible thunderstorms. Urban flooding in low-lying streets and underpasses remains a possibility when heavy rain coincides with high tide or drainage limitations.
The Rest of Luzon and Western Visayas
Areas not already listed under heavier rainfall categories — including the remainder of Luzon and the western portions of the Visayas — can expect partly cloudy to cloudy skies with isolated showers or thunderstorms. PAGASA links this to the Southwest Monsoon as well, and notes the possibility of flash floods or landslides if thunderstorms become severe. These conditions are less persistent but can still be intense when they occur.
Eastern Visayas and Mindanao: Localized Thunderstorm Risk
The rest of the country — which includes eastern Visayas and most of Mindanao — will see partly cloudy to cloudy skies with isolated rainshowers or thunderstorms. In these areas, the driver is localized thunderstorm activity rather than the monsoon, meaning the rain will be more scattered and unpredictable in timing and location. Flash floods and landslides remain possible during any severe thunderstorm, so Mindanao residents should not dismiss the forecast as benign simply because conditions appear fair for much of the day.
Winds and Coastal Waters
At sea, conditions are notably hazardous off western and northern coasts. PAGASA reports that coastal waters around Luzon and the western section of Visayas will be moderate to rough today, driven by moderate to strong winds blowing from the southwest. The rest of the country will see lighter winds from the south to southwest, with coastal waters ranging from slight to moderate, with wave heights of 0.6 to 2.1 meters.
Moderate to rough seas can capsize small boats and make navigation extremely difficult for fishermen without proper equipment. PAGASA strongly advises small sea vessels to exercise caution or avoid venturing into affected waters altogether.
Decoding the Warnings: What Each Risk Level Means for You
PAGASA's forecast for today does not include active tropical cyclone wind signals, but the bulletin does flag rainfall-related hazards — specifically the risk of flash floods and landslides — for multiple areas across Luzon and parts of the Visayas. These are not abstract possibilities: flash floods can develop within minutes of intense rainfall, and landslides can occur on slopes that appear stable under ordinary conditions.
If your community is near a river, a hillside, or a known flood-prone area, treat today's forecast seriously. Avoid crossing flooded roads or waterways, even if the water appears shallow. For a full guide on understanding PAGASA's warning systems, including rainfall color codes and storm signals, read how to read PAGASA's weather warnings.
What It Means for You
Commuters
Metro Manila and surrounding provinces face a day of on-and-off rain with the potential for heavy bursts and thunderstorms. Allow extra travel time, avoid flood-prone underpasses and low-lying streets, and keep an eye on real-time traffic and flood advisories from local government units and PAGASA. Bring rain gear — the weather today is unlikely to clear for extended periods.
Fisherfolk and Small-Boat Operators
The situation at sea off Luzon and western Visayas is the most pressing concern today. Moderate to rough coastal waters pose a serious safety hazard for small fishing vessels and bancas. PAGASA urges caution. If you are a small-boat operator in these areas, the safest decision today is to stay ashore until conditions improve. Those operating off eastern Visayas and Mindanao face lighter conditions, but isolated thunderstorms can produce sudden squalls even in otherwise calm-looking seas — stay alert.
Farmers
Farmers in Ilocos Norte, Ilocos Sur, La Union, and Pangasinan face the highest risk from today's rainfall. Heavy rain can damage crops, erode topsoil, and flood low-lying fields. Secure farm equipment and check drainage in fields. Farmers in Metro Manila, Central Luzon, and Antique should also monitor conditions throughout the day given the forecast of scattered heavy rains.
Students, Parents, and Schools
Class suspensions are decided by local government units, not PAGASA, but today's forecast — particularly for northern Luzon and Metro Manila — warrants close monitoring. Parents in Ilocos Norte, Ilocos Sur, La Union, Pangasinan, and Metro Manila should track local announcements and prepare for the possibility of disruptions. Given that heavy rain can develop quickly under monsoon conditions, keep children's rain gear packed and have a contingency plan ready.
Outdoor Workers and Construction Sites
Those working outdoors across Luzon — especially in exposed or elevated areas — should be prepared to suspend work if heavy rain and lightning begin. Landslide risk is elevated today in mountainous provinces, including the Cordillera Administrative Region. Supervisors at hillside construction sites should have clear protocols for when to evacuate workers to safe ground.
Temperature and Humidity
PAGASA's 24-hour observation period ending 8:00 PM yesterday, recorded at the PAGASA Weather Station in Science Garden, Diliman, Quezon City, logged a maximum temperature of 31.3°C at 1:00 PM and a minimum of 27.5°C at 5:00 AM. Relative humidity peaked at 82% at 8:00 AM and dipped to a minimum of 71% at 11:00 PM. These figures reflect the warm, humid baseline of late August in Metro Manila — even on a rainy day, temperatures remain high enough to feel uncomfortable when the rain temporarily stops and the sun breaks through.
Tides Over Metro Manila
For Metro Manila, PAGASA records a high tide of 1.28 meters at 6:00 AM today. A low tide of 0.09 meters is expected at 5:00 PM. Sunrise is at 5:48 AM and sunset at 6:12 PM. When heavy rainfall coincides with high tide periods, urban flooding risk in coastal barangays and low-lying streets intensifies — a factor that Metro Manila residents and local authorities should keep in mind particularly during morning hours.
Bottom Line
If you are in northern or western Luzon — particularly Ilocos Norte, Ilocos Sur, La Union, and Pangasinan — treat today as a high-alert day for flash floods and landslides. The Southwest Monsoon is directing its heaviest rain at these areas. Metro Manila and surrounding provinces also face scattered heavy thunderstorms. Across the rest of the country, stay aware that isolated but intense thunderstorms can strike even in areas with generally fair skies. At sea off Luzon and western Visayas, small vessels should stay in port. Stay informed and prepared — weather conditions today have the potential to deteriorate quickly.
Monitor official PAGASA updates at pagasa.dost.gov.ph