QUEZON CITY, November 1, 2026 — Parts of Northern Luzon face the threat of flash floods and landslides this Sunday as a shear line drives scattered rains and isolated thunderstorms over several provinces, while the northeast monsoon keeps conditions cloudy and unsettled across the northern reaches of the country. The rest of the Philippines will not be entirely dry, either — localized thunderstorms could bring brief but intense downpours from Metro Manila all the way down to Mindanao, according to the 4:00 AM weather bulletin issued by the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA), valid until 4:00 AM on Monday, November 2, 2026.
What Is Driving Today's Weather
Two weather systems are at work over the Philippines today. The first is a shear line affecting the eastern section of Northern Luzon. A shear line forms when two air masses moving in different directions meet, creating a boundary where moisture is squeezed upward into the atmosphere — producing clouds, rain, and in some cases, intense downpours. This is the primary reason why provinces like Cagayan, Apayao, Kalinga, and Isabela are seeing the heaviest and most persistent rainfall today.
The second system is the northeast monsoon, locally known as amihan, which is now influencing the rest of Northern Luzon. The amihan is a seasonal wind pattern that brings cool, moist air from the northeast across the northern Philippines during the latter months of the year. It typically produces cloudy skies and light, on-and-off rain — conditions felt today across Batanes, Babuyan Islands, Ilocos Norte, Abra, and Benguet.
For Metro Manila and the rest of the country, localized thunderstorms — weather systems that develop on their own due to daytime heating rather than a large external system — are responsible for any rain showers or thunderstorms expected today.
PAGASA also notes that Typhoon In-fa (2631) — carrying maximum sustained winds of 155 km/h and gusts of up to 190 km/h — is located approximately 2,290 kilometers east of extreme Northern Luzon, moving east-northeastward at 10 km/h. The typhoon is outside the Philippine Area of Responsibility (PAR) as of 3:00 AM today and is not influencing local weather conditions. No tropical cyclone wind signals have been raised anywhere in the country in connection with this system.
Region-by-Region Forecast
Northern Luzon — Shear Line and Amihan at Work
The heaviest rain in the country today falls across Mainland Cagayan, Apayao, Kalinga, and Isabela, where the shear line is producing cloudy skies with scattered rains and isolated thunderstorms. PAGASA warns that these conditions could trigger flash floods and landslides, particularly during moderate to heavy rain episodes. Residents in low-lying and mountainous areas of these provinces are advised to stay alert and monitor local conditions.
Meanwhile, Batanes, Babuyan Islands, Ilocos Norte, Abra, and Benguet — under the influence of the northeast monsoon — can expect partly cloudy to cloudy skies with isolated light rains. PAGASA has flagged no significant hazards for these areas today.
Metro Manila and the Rest of Luzon
The National Capital Region and the remaining provinces of Luzon not mentioned above will experience partly cloudy to cloudy skies with isolated rain showers or thunderstorms. These will be driven by localized thunderstorm activity rather than a large-scale weather system. While conditions may look manageable for much of the day, PAGASA cautions that flash floods and landslides remain possible in areas that experience severe thunderstorms.
Visayas
The Visayas region also falls under the "rest of the country" category in today's PAGASA bulletin, meaning residents across the Eastern, Central, and Western Visayas can expect partly cloudy to cloudy skies with isolated rain showers or thunderstorms triggered by localized convective activity. The same caution applies: brief but potentially intense thunderstorms could lead to localized flash flooding.
Mindanao
Mindanao is likewise covered by the same general forecast — partly cloudy to cloudy skies with isolated rain showers or thunderstorms from localized thunderstorm activity. Flash floods and landslides remain a risk should severe thunderstorms develop in any part of the region. Residents in mountainous and flood-prone areas should take the standard precautions.
Wind and Sea Conditions
Fisherfolk and maritime workers should take note of the following sea conditions issued by PAGASA:
Over Luzon and Visayas, winds will be light to moderate, blowing from the northeast to east. Coastal waters will be slight to moderate, with wave heights ranging from 0.6 to 2.5 meters.
Over Mindanao, winds will also be light to moderate, coming from the southeast to east. Coastal waters will be slight to moderate, with wave heights of 0.6 to 1.8 meters.
While no gale warnings have been raised, the moderate sea state — particularly at the higher end of 2.5 meters for Luzon and Visayas — warrants caution for operators of small and bancа vessels.
Decoding Today's Warnings
PAGASA has not raised any tropical cyclone wind signals in connection with Typhoon In-fa, as the storm remains well outside PAR. However, the bulletin does flag the hazard of flash floods and landslides for areas under the shear line (Cagayan, Apayao, Kalinga, and Isabela) and the potential for the same hazard nationwide during severe localized thunderstorms.
If you are unsure about what different warning levels mean and how to respond to them, our guide on how to read PAGASA's weather warnings breaks down rainfall color-coded alerts, tropical cyclone wind signals, and heat index categories in plain language.
No yellow, orange, or red rainfall warnings have been specifically cited in today's bulletin beyond the general flash flood and landslide hazard language. Residents in Cagayan, Apayao, Kalinga, and Isabela should monitor PAGASA and local disaster risk reduction offices for any updates to these hazard assessments as the day progresses.
What Today's Weather Means for You
Commuters in Metro Manila and other urban centers should be prepared for the possibility of rain showers or thunderstorms at any point during the day. Localized thunderstorms can develop quickly, so carrying an umbrella or raincoat is practical advice. Be aware of low-lying streets and underpasses that may flood rapidly during heavy downpours.
Fisherfolk and small-boat operators across Luzon and Visayas should take note of wave heights potentially reaching 2.5 meters in coastal waters — classified by PAGASA as the upper end of the moderate sea state. Extra caution is advised, and small banca operators in particular should assess whether conditions are safe before heading out. Those operating off Mindanao face slightly lower wave heights, topping out at 1.8 meters, but the same degree of prudence applies.
Farmers in Cagayan, Apayao, Kalinga, and Isabela face the most pressing concern today. Moderate to heavy rains from the shear line can waterlog fields and trigger landslides in elevated agricultural areas. Farmers in these provinces should secure equipment and check on irrigation drainage to prevent crop damage.
Students, parents, and school administrators across Northern Luzon — especially in the provinces affected by the shear line — should monitor advisories from the Department of Education and local government units regarding any school suspensions. The risk of flash floods on access roads is real in these areas today.
Outdoor workers and construction crews throughout the country should be prepared for brief work stoppages due to isolated thunderstorms. Workers in the Cagayan Valley region and adjacent shear-line-affected provinces face the highest risk of rain disruption today, and those working near slopes or waterways should be especially vigilant about landslide and flash flood hazards.
Temperature Outlook
PAGASA's weather station at Science Garden in Diliman, Quezon City recorded a maximum temperature of 33.3°C at 2:00 PM yesterday and a minimum of 24.1°C at 5:00 AM yesterday. Relative humidity peaked at 94% at 5:00 AM and dipped to a minimum of 54% at 2:00 PM. These figures reflect conditions recorded at that specific station for the 24-hour period ending 8:00 PM yesterday and serve as a reference point for Metro Manila's recent thermal conditions.
No heat index warnings have been issued in today's bulletin.
Astronomical and Tidal Notes for Metro Manila
For those planning activities in Manila Bay or nearby coastal areas, PAGASA notes the following tidal data courtesy of NAMRIA: High tide is at 1:06 AM at 1.22 meters, and low tide is at 10:36 AM at -0.21 meters. Sunrise today is at 5:51 AM and sunset at 5:28 PM. The moon rises at 11:28 PM with a 54% illumination.
Bottom Line
If you are in Cagayan, Apayao, Kalinga, or Isabela today, treat the risk of flash floods and landslides seriously — the shear line will keep rains coming, and conditions can deteriorate quickly in low-lying and mountainous areas. For everyone else across the Philippines, the day will see patches of sunshine interrupted by isolated thunderstorms — be ready for rain at any time and avoid flood-prone areas during heavy downpours.
Monitor official PAGASA updates at pagasa.dost.gov.ph.