A large portion of the Philippines faces an unsettled Friday as the southwest monsoon — known locally as habagat — maintains its grip on Central Luzon, Southern Luzon, and Visayas, according to the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA). The agency's 24-hour public weather forecast, issued at 4:00 AM on Friday, September 11, 2026, warns of flash flood and landslide hazards across multiple provinces, and remains valid until 4:00 AM on Saturday, September 12.
Even areas outside the monsoon's direct influence are not spared: localized thunderstorms are expected to bring short but potentially intense downpours to the rest of Visayas and Mindanao through the day and into the evening.
What Is Driving Today's Weather?
The primary driver today is the southwest monsoon, or habagat — a seasonal wind system that blows warm, moisture-laden air from the southwest across the Philippine archipelago typically from June through September. When this moisture-rich airflow meets the country's mountain ranges and coastlines, it is forced upward, cools, and produces heavy, widespread rainfall. Today, PAGASA says it is directly affecting Central Luzon, Southern Luzon, and Visayas, making these regions the most vulnerable to sustained and heavy rain.
The rest of the country — areas not directly in the monsoon's path — will instead contend with localized thunderstorms, which are intense but more scattered weather events that can still cause dangerous flash flooding when they strike a single location with concentrated rainfall in a short period.
Region-by-Region Forecast
Northern and Central Luzon
PAGASA forecasts occasional rains for Pangasinan, La Union, Benguet, Zambales, and Bataan, all driven by the southwest monsoon. The agency specifically flags the potential for moderate to heavy rains in these provinces, warning of possible flash floods and landslides as a result. Residents in low-lying coastal areas and mountainous communities — particularly in Benguet, where terrain makes landslides a recurring hazard — should be especially alert.
Metro Manila and the Rest of Luzon
Residents of Metro Manila and the broader Luzon region face one of the more challenging weather days of this forecast period. PAGASA expects cloudy skies with scattered rains and thunderstorms, also fueled by the southwest monsoon. Rainfall intensity is forecast to reach moderate to at times heavy levels, with explicit warnings that flash floods and landslides are possible. Commuters and outdoor workers throughout the capital region and surrounding provinces should anticipate disruptions to travel and daily routines.
Western Visayas and Northern Samar
The monsoon extends its reach southward into the Visayas, with Western Visayas and Northern Samar sharing the same forecast as Metro Manila: cloudy skies with scattered rains and thunderstorms, moderate to at times heavy rainfall, and the associated risk of flash floods and landslides. Communities near rivers and mountain slopes in these areas should remain vigilant throughout the day.
The Rest of Visayas and Mindanao
The remainder of the Visayas and all of Mindanao are expected to experience partly cloudy to cloudy skies with isolated rainshowers or thunderstorms, produced by localized thunderstorm activity rather than the southwest monsoon itself. While conditions are generally less severe than in Luzon and Western Visayas, PAGASA notes that flash floods remain possible in areas that experience severe thunderstorm episodes. Afternoon and evening hours are typically when localized thunderstorms are most active.
Decoding the Hazard Warnings
PAGASA's forecast does not issue specific color-coded rainfall warnings or tropical cyclone wind signals in this bulletin, but it does explicitly name flash floods and landslides as hazards for areas under monsoon influence. This means PAGASA considers the expected rainfall intensity sufficient to pose a genuine risk to life and property — not merely an inconvenience.
For a clear explanation of how the agency's warning systems work — including what rainfall colors, storm signals, and heat index categories actually mean — read our guide on how to read PAGASA's weather warnings.
If you live or work near rivers, streams, drainage canals, or slopes — especially in Benguet, Zambales, Bataan, La Union, Pangasinan, Northern Samar, and Western Visayas — treat these flash flood and landslide notices as a prompt to review your evacuation plan and keep emergency contacts ready.
Sea and Wind Conditions: Caution for Coastal Areas
PAGASA forecasts light to moderate winds and slight to moderate coastal waters across the country, with the following wave height estimates:
- Northern Luzon: Southeast to northeast winds; wave heights of 0.6 to 2.5 meters — the roughest seas in the country today.
- Visayas and the rest of Luzon: Southwest to south winds; wave heights of 0.6 to 1.8 meters.
- Mindanao: South to southwest winds; wave heights of 0.6 to 1.8 meters.
Wave heights of up to 2.5 meters in Northern Luzon in particular represent conditions that small, motorized bancas and fishing boats are not designed to safely handle. Even in areas where waves are on the lower end of the forecast range, conditions can change rapidly, especially near river mouths and coastal waters exposed to monsoon winds.
What It Means for You
Commuters
If you travel through Metro Manila, Central Luzon, or Western Visayas, expect the possibility of flooded streets, particularly in low-lying areas and those near waterways. Leave earlier than usual, and monitor local government social media pages and radio for real-time flood advisories. If floodwater reaches knee level, do not attempt to cross on foot or by vehicle.
Fisherfolk and Small-Boat Operators
Wave heights of up to 2.5 meters in Northern Luzon and 1.8 meters in other coastal areas make conditions unsafe for small vessels today. PAGASA strongly advises small boat operators across all coastal areas to exercise caution. The safest choice for operators of small, non-motorized, or lightly motorized boats is to remain ashore, particularly in Northern Luzon waters.
Farmers
Moderate to heavy monsoon rains bring both opportunity and risk. Farmers in Luzon and Western Visayas should secure harvested crops and check drainage in low-lying fields to prevent waterlogging. Those in slope areas — particularly in Benguet and the Cordillera — should watch for signs of soil saturation and avoid working on steep hillside farms during peak rainfall hours.
Students, Parents, and School Administrators
With flash flood risks flagged across much of Luzon and Western Visayas, school administrators and local government units in affected provinces should monitor conditions closely and be prepared to implement suspension protocols. Parents in flood-prone barangays should keep children home if flooding begins, in line with local disaster risk reduction guidelines.
Outdoor Workers and Construction Crews
Heavy rain and thunderstorms raise the risk of lightning strikes, slippery scaffolding, and unstable ground — all of which are occupational hazards for construction and outdoor workers. Supervisors in Metro Manila, Central Luzon, and Western Visayas should have clear protocols for suspending outdoor work when thunderstorms approach.
Temperature Outlook
PAGASA's Science Garden station in Diliman, Quezon City recorded a maximum temperature of 30.2°C at 12:00 noon and a minimum of 24.5°C at 6:00 AM for the 24-hour period ending 8:00 PM on September 10. Relative humidity ranged from 68% to 95%, reflecting the heavy moisture in the air consistent with active monsoon conditions. While these figures are specific to Quezon City, they give a useful indication of warm and humid conditions persisting across the low-lying areas of Luzon under monsoon influence.
Despite the rain, temperatures remain warm — residents should stay hydrated, especially during any brief sunny breaks between showers.
Sunrise, Sunset, and Tidal Information
For Metro Manila on September 11, 2026, the sun rises at 5:45 AM and sets at 6:01 PM. The moon rises at 5:35 AM and sets at 6:03 PM, with zero percent illumination — a new moon night, meaning very dark conditions after sunset. This is worth noting for those traveling in flood-prone areas after dark, where visibility will be limited.
Manila Bay tides today: low at 2:08 AM (0.43 m), high at 9:53 AM (1.26 m), low at 5:18 PM (0.16 m), and high at 11:06 PM (0.60 m), according to tidal predictions from NAMRIA courtesy of PAGASA.
Bottom line: The southwest monsoon is bringing genuine flash flood and landslide risk to Metro Manila, Central Luzon, several Northern Luzon provinces, Western Visayas, and Northern Samar today — Friday, September 11, 2026. If you live or work in these areas, the single most important thing you can do today is identify the safest elevated route or location near you before the heaviest rains arrive, and act on any local evacuation order immediately rather than waiting to see how high the water rises.
Monitor official PAGASA updates at pagasa.dost.gov.ph