MINDANAO — Residents across Mindanao are being advised to remain alert for rainshowers and thunderstorms as the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) forecast partly cloudy to cloudy skies with isolated rainshowers or localized thunderstorms across the region from Friday morning, August 21, until Saturday morning, August 22, 2026.
The Regional Weather Forecast for Mindanao, issued by the PAGASA Mindanao–Philippine Regional Services Division (MINPRSD) at 5:00 a.m. on August 21, said localized thunderstorms could become severe in some areas, potentially triggering flash floods and landslides, particularly in communities vulnerable to sudden heavy rainfall.
PAGASA’s forecast is valid from 5:00 a.m. Friday until 5:00 a.m. Saturday, covering the Zamboanga Peninsula, Northern Mindanao, Davao Region, SOCCSKSARGEN, Caraga and the Bangsamoro Autonomous Region in Muslim Mindanao (BARMM).
Across Mindanao, winds are expected to remain light to moderate and generally coming from the south to southwest, while coastal waters will range from slight to moderate, with wave heights estimated at 0.6 to 2.1 meters.
The weather pattern means that generally fair or partly cloudy conditions may still be interrupted by sudden periods of heavy rain and thunderstorms. PAGASA’s warning on possible flash floods and landslides is particularly significant because intense rainfall from localized thunderstorms can produce rapid runoff even when widespread rain is not occurring.
Zamboanga Peninsula
Zamboanga City and the provinces of Zamboanga del Norte, Zamboanga del Sur and Zamboanga Sibugay, as well as Isabela City, are expected to experience partly cloudy skies becoming cloudy at times, with rainshowers or thunderstorms.
Temperatures are forecast to range from 24°C to 35°C, with Isabela City potentially recording the highest daytime temperature at 35°C. Coastal waters will remain slight to moderate, with winds from the south to southwest.
Northern Mindanao
The same weather conditions are expected in Bukidnon, Camiguin, Lanao del Norte, Misamis Occidental and Misamis Oriental.
Bukidnon is forecast to have temperatures between 20°C and 33°C, while Camiguin, Lanao del Norte and Misamis Occidental could see temperatures generally between 24°C and 34°C. Misamis Oriental may reach 35°C during the warmer part of the forecast period.
Residents in mountainous and elevated areas should remain particularly watchful during thunderstorms because saturated or heavily watered slopes can become vulnerable to landslides.
Davao Region
The Davao Region will likewise experience partly cloudy to cloudy skies with rainshowers or thunderstorms.
Metro Davao is forecast to record temperatures of 26°C to 33°C, while Davao del Norte, Davao del Sur, Davao Oriental, Davao de Oro and Davao Occidental are expected to have temperatures generally ranging from the low to mid-20s up to 34°C.
Coastal areas in the region will have slight to moderate seas, with south-to-southwest winds prevailing.
SOCCSKSARGEN
In North Cotabato, South Cotabato, Sultan Kudarat and Sarangani, partly cloudy to cloudy conditions with rainshowers or thunderstorms are also expected.
Temperatures could reach 34°C in North Cotabato and Sultan Kudarat, while Sarangani is expected to range from 25°C to 33°C.
The forecast also calls for slight to moderate coastal conditions in areas with exposed shorelines.
Caraga
Thunderstorms and rainshowers are also possible across Agusan del Norte, Agusan del Sur, Surigao del Norte, Surigao del Sur and the Dinagat Islands.
Surigao del Norte and Dinagat Islands could experience some of the warmer conditions in the region, with temperatures reaching up to 36°C. Agusan del Norte could reach 35°C, while Agusan del Sur and Surigao del Sur may reach 34°C.
Despite the relatively warm temperatures, localized thunderstorms may bring sudden heavy rainfall, making flood-prone communities and landslide-prone areas vulnerable to rapid changes in weather conditions.
BARMM
The Bangsamoro Autonomous Region in Muslim Mindanao will also remain under the same general weather pattern.
Cotabato City, Basilan, Lanao del Sur, Sulu, Tawi-Tawi, Maguindanao del Norte and Maguindanao del Sur are forecast to experience partly cloudy to cloudy skies with rainshowers or thunderstorms.
Temperatures are expected to range from around 20°C to 34°C, with Basilan potentially reaching 34°C and Lanao del Sur remaining among the cooler areas, with temperatures of about 20°C to 32°C.
Sulu and Tawi-Tawi are forecast to experience temperatures of 26°C to 33°C, while Maguindanao del Norte and Maguindanao del Sur could reach 33°C.
With many BARMM communities located near rivers, low-lying areas and mountainous terrain, residents are advised to remain attentive to sudden downpours and possible flooding or landslides during severe thunderstorms.
PAGASA urges vigilance
The regional forecast does not indicate continuous widespread rainfall across Mindanao. Instead, the primary concern is the possibility of isolated or localized thunderstorms, which can develop rapidly and produce intense rainfall over specific areas.
PAGASA’s warning means residents should not assume that generally partly cloudy conditions guarantee safe weather throughout the day. Thunderstorms may develop suddenly, bringing heavy rain, strong gusts and potentially hazardous conditions.
Communities in low-lying and flood-prone areas, as well as those near rivers and streams, should monitor rainfall and water levels. Residents in mountainous and landslide-prone communities are likewise encouraged to stay alert for signs of slope instability following periods of heavy rain.
Motorists should exercise caution when traveling during thunderstorms because reduced visibility, slippery roads and sudden flooding can increase the risk of accidents.
For fishermen and small-craft operators, the forecast of slight to moderate seas and waves of 0.6 to 2.1 meters also calls for continued caution, particularly when thunderstorms are occurring near coastal waters.
PAGASA advised the public to monitor subsequent weather bulletins and warnings for updates, particularly if thunderstorms intensify or conditions change.