PAGASA has declared the start of the southwest monsoon. Heavy rain, flooding, and landslides have already begun across the country. Here is why the first rains matter for your exact address, and how to check flood and landslide risk before the season peaks.
PAGASA declared the onset of the southwest monsoon, the habagat, on May 30, 2026. The rainy season is officially here. Within days, a low-pressure area and the habagat were already bringing heavy rain, flooding, and landslides across parts of Luzon, Visayas, and Mindanao.
If you own a home, are about to buy one, or plan for a community, this is the window to know your flood risk. Not during the first big storm. Now.
The early storms of the season are when low spots reveal themselves. Streets that looked fine in the dry months turn into shallow rivers. A lot that drains well most of the year shows whether it actually sheds water or collects it.
The problem is that by the time you see it with your own eyes, you may already live there. Checking the hazard map first lets you know what to expect before the water arrives.
Two houses a few doors apart can have very different flood risk. A small dip in elevation, an old creek that was filled in, or being one block closer to a river can be the whole difference.
That is why CheckHazard reads risk for the exact point, not the general area. It checks which flood zones the lot falls into and at what return period, so you can tell frequent nuisance flooding apart from rare but deep flooding. If the difference is new to you, the flood layer brief explains what a "5-year" versus "100-year" flood really means.
Heavy, sustained rain does not just flood low ground. It soaks slopes until the soil loses its grip, and that is when landslides happen. Properties at the foot of a steep hill, or perched on a cut slope, carry this risk even when they sit well above any floodwater.
CheckHazard reads slope and landslide susceptibility for the address too, so a home that is safe from flooding but exposed on a slope does not slip through. See the landslide and elevation and slope briefs for how we read those.
PAGASA's own outlook is a reason not to wait. The agency expects roughly 9 to 13 tropical cyclones to form within or enter the Philippine area from June to November. Some of those will be the real tests of any property.
Type the address into CheckHazard and you get flood, landslide, waterway proximity, and the rest for that exact spot, for ₱99, in seconds. It tells you which risks to watch this season and which questions to bring to a closer look.
CheckHazard is decision-support, not a replacement for a licensed geotechnical or engineering survey. Drainage, recent construction nearby, and the specific lot can all change real-world flooding in ways a map cannot fully capture. Use the reading to know what to check on the ground.