In the Philippines, a country better known for its tropical warmth and balmy weather, the occurrence of hailstorms has traditionally been regarded as a rare anomaly. However, a pioneering study, representing the first comprehensive examination of hail events within the archipelago, has now unveiled a surprising and counterintuitive climatic behavior: the nation’s hottest days are disproportionately more likely to spawn hailstorms. This groundbreaking research not only challenges preexisting notions about tropical weather phenomena but also offers new insights into the intricate relationship between heat, atmospheric dynamics, and severe weather occurrences.
Hailstorms in the Philippines have historically been few and far between, often capturing public attention through social media posts when they do happen. Despite the country’s typical weather profile dominated by tropical heat and humidity, hail has occasionally made striking appearances—most famously on May 8, 2020. On that day, the largest hailstones ever recorded in the Philippines were documented in Cabiao, Nueva Ecija, with diameters reaching up to 5 centimeters, surpassing the size of a standard golf ball. Meteorological experts have cited this event as a critical case study for understanding hail formation in tropical environments, which are not generally conducive to the ice precipitation phenomena more commonly associated with colder climates.
At the heart of this weather paradox lies a fundamental atmospheric process powered by Convective Available Potential Energy, or CAPE. CAPE quantifies the amount of energy available for upward air movement, which is pivotal for the development of convective storms. Elevated surface temperatures lead to stronger thermal convection, propelling warm, moist air skyward into the colder reaches of the troposphere. When this upward transport occurs robustly, water droplets ascend into freezing atmospheric layers and undergo cycles of accumulation and freezing, ultimately forming hailstones large enough to survive the descent to the surface.
Another critical meteorological factor that amplifies the likelihood of hail in the Philippines is the presence of dry air masses at mid-tropospheric levels. This dry air causes evaporative cooling, which strengthens downdrafts—downward-moving air currents—that accelerate the passage of hailstones through warmer atmospheric layers below. The reduced melting time during the rapid fall allows these ice particles to maintain their size and reach the ground intact, explaining the observed survival of large hailstones despite the generally warm tropical atmosphere.
The comprehensive study, spanning data from nearly two decades between 2006 and 2024, meticulously analyzed hail occurrences using an array of observational and modeling tools. Satellite imagery from the HIMAWARI-8 weather satellite, combined with radar reflectivity scans and high-resolution weather simulations, allowed researchers to identify the specific atmospheric conditions accompanying hail events. These tools revealed strong updrafts and concentrated precipitation areas associated with episodes of significant hail formation, notably during the dry season months of March, April, and May — periods characterized by soaring surface temperatures and volatile convective activity.
Intriguingly, while the largest number of hail reports originated from Luzon, the study found that the most sizable hailstones were more frequently noted in the Visayas and Mindanao regions. This spatial distribution relates to differences in monsoonal influence; the Southwest Monsoon tends to suppress localized convective storms in Luzon as the season progresses, while its reduced presence in the central and southern Philippines allows more intense convective development to persist later in the year. These findings highlight the complex interplay between large-scale regional climate drivers and localized storm dynamics.
Beyond purely scientific recordings, the researchers placed great value on incorporating citizen science and public reporting into their dataset. Due to limited ground-based hail detection infrastructure within the Philippines, the inclusion of geotagged social media posts, local news reports, and government records enriched the spatial and temporal resolution of hail event documentation. This crowd-sourced, multi-source strategy proved pivotal in constructing a robust picture of hailstorm frequency and distribution across a vast and topographically complex nation.
The study’s revelations underscore the urgent need to expand weather monitoring capabilities within tropical countries like the Philippines, where traditional weather hazards such as typhoons and floods have long dominated disaster preparedness efforts. As climate change continues to escalate atmospheric instability and the frequency of extreme events, lesser-known hazards such as hailstorms, tornadoes, and waterspouts can pose unforeseen threats to communities. Developing early warning systems that account for a broader spectrum of severe weather phenomena will be key to mitigating risks in vulnerable regions.
From a meteorological point of view, hail formation in tropical climates challenges the conventional understanding that such events are predominantly linked with colder environments. The Philippines study demonstrates that under sufficient thermal convection and atmospheric instability, even the warm tropics can generate the intense ice precipitation usually reserved for midlatitude or polar regions. This revelation has broader implications for climate models and weather prediction, calling for adjustments that incorporate tropical hail dynamics into forecasting algorithms.
Moreover, the methodology of combining satellite data with ground-level reports and atmospheric modeling represents a scientific paradigm for studying infrequent or poorly monitored weather events. Given the Philippines’ archipelagic geography and limited technological resources, this innovative hybrid approach provides a roadmap for other tropical regions seeking to understand similarly elusive phenomena. The role of citizen contributors in science is thus amplified, exemplifying how public engagement can complement formal scientific inquiry to enhance environmental surveillance.
Ultimately, the research team led by Dr. Lyndon Mark P. Olaguera, together with colleagues from DOST-PAGASA and the Ateneo de Manila University, has laid a strong foundation for future investigation into tropical hail. Their findings encourage sustained efforts to improve observational networks, foster interdisciplinary collaboration, and raise public awareness about the nuanced and evolving risks posed by extreme weather events in the tropics. As the planet warms and weather patterns become increasingly volatile, such research assumes critical importance in safeguarding the millions who live under tropical skies.
This landmark study, published in the Asia-Pacific Journal of Atmospheric Sciences, represents a paradigm shift in our understanding of tropical meteorology. By revealing the disguised presence of severe convective phenomena like hailstorms in the Philippines, it challenges prevailing assumptions and offers vital data for climate adaptation strategies. As communities grapple with the mounting challenges of climate change, recognizing and preparing for even the rarest atmospheric events will be essential to building resilient futures.
Subject of Research: Hailstorm occurrences and their meteorological drivers in the Philippines
Article Title: Spatiotemporal Analysis of Hail Events in the Philippines
News Publication Date: 10-Jul-2025
Web References: 10.1007/s13143-025-00409-4
References: Ibañez et al., 2025
Image Credits: Ibañez et al., 2025
Keywords: tropical hailstorms, convective available potential energy, CAPE, Philippines weather, atmospheric convection, hail formation, tropical meteorology, satellite meteorology, climate change impacts, extreme weather, Doppler radar, citizen science
