SW Monsoon to bring rains, thunderstorms across Luzon
La Union and the Ilocos Region can expect isolated thunderstorms and possible flash floods from the monsoon
Screenshot of Himawari-9 viewer, credit Meteorological Satellite Center / Japan Meteorological Agency (JMA)
PAGASA said on 21 July 2026 the Southwest Monsoon is affecting western sections of Luzon today, bringing scattered rains and isolated thunderstorms to parts of Luzon including the Ilocos Region and may cause flash floods or landslides during heavy storms.
The national forecast lists scattered to isolated rain across several regions. For the Ilocos Region — which includes La Union — PAGASA expects partly cloudy to cloudy skies with isolated rainshowers or thunderstorms, and added that severe thunderstorms could trigger flash floods or landslides in exposed areas.
Key details from PAGASA:
- Main system: Southwest Monsoon affecting western Luzon and other areas today.
- Local impact (Ilocos Region / La Union): Partly cloudy to cloudy, isolated rainshowers or thunderstorms, possible flash floods or landslides during heavy storms.
- Wind and coastal waters: Rest of Luzon to have light to moderate south to southwest winds with slight to moderate seas (0.6 to 1.5 meters) — relevant for La Union’s coastal waters.
- Wider areas listed: Western Visayas, Negros Island Region, Zamboanga Peninsula, BARMM, Metro Manila, Cordillera, MIMAROPA, Batanes, Babuyan Islands, Zambales, Bataan, Cavite, Batangas, and Mindanao.
PAGASA also reported recent observational data from its Diliman station: a maximum temperature of 33.5°C and relative humidity peaking at 87% in the previous 24-hour period. The agency continues to monitor the monsoon and issues region-specific advisories as conditions evolve.
SOURCE: PAGASA