Philippines Faces Growing Risks to Food Supply and Crops Amid Monsoon Variability

The Philippines is increasingly facing risks to its agricultural production and food supply due to shifts in monsoon patterns, with the southwest monsoon, known locally as Habagat, lingering longer into the "Ber months" (September to December), which traditionally signal cooler, drier weather. Heavy flooding across Central Luzon and Metro Manila in late August 2026 exemplified the destructive impact of this monsoon variability. Rainfall totals exceeded 300 to 400 millimeters in just three days, a volume historically spread across a month. The Pampanga and Pasig rivers overflowed, and urban drainage systems were overwhelmed by the concentrated rainfall. This phenomenon is attributed to a combination of interacting drivers: atmospheric dynamics, ocean warming, topographic amplification, climate change, and ecological degradation. Together, these factors contribute to the persistence of Habagat into the Ber months, disrupting what was once a predictable seasonal transition. The expectation that the Ber months mean Amihan has weakened amid climate variability and ecological disruption. Extended Habagat seasons are reshaping the agricultural and disaster risk landscapes of Luzon. Scientific evidence cited in this report points to atmospheric interactions, ocean warming, ENSO variability, and ecological degradation as drivers of this shift. Together, they intensify rainfall, delay the onset of cooler winds, and increase flood risks across rice-producing areas and urban centers. The Philippines, an archipelagic nation in the western Pacific, has long been defined by its monsoon cycles. The southwest monsoon, locally known as Habagat, traditionally dominates from June to September, bringing heavy rains that sustain rice cultivation and replenish water systems. The northeast monsoon, Amihan, ushers in cooler, drier air from Siberia beginning in late September, marking the start of the so-called Ber months. This seasonal rhythm historically provided a reliable framework for agricultural planning, disaster preparedness, and cultural expectations. Farmers aligned their cropping calendars with the anticipated arrival of Amihan, while communities prepared for reduced flood risks and cooler weather. In recent decades, however, Habagat rains have persisted well into September and October, undermining traditional expectations and exposing systemic vulnerabilities. Historically, the monsoon transition was considered predictable. Pagasa records from the 1960s through the 1980s show that Amihan typically arrived by mid-September, stabilizing weather conditions and enabling rice harvests in Central and Northern Luzon (David, 2009). This predictability allowed farmers to rely on sun-drying methods for post-harvest processing, helping ensure that grain moisture levels met IRRI standards. Flood risks also declined by late September, allowing government agencies to shift their focus from relief operations to storage and distribution. By the 1990s, however, anomalies had begun to emerge. The 1995 La Niña event delayed the onset of Amihan by nearly a month, causing widespread flooding in Central Luzon and disrupting rice harvests. Similar disruptions occurred in 2011 and 2020, when extended Habagat rains led to crop losses exceeding 200,000 metric tons (FAO, 2021). The persistence of Habagat into the Ber months is driven by multiple scientific factors. Atmospheric interactions between cooler Amihan winds and moisture-laden Habagat flows intensify rainfall rather than suppress it. Oceanic drivers, particularly warmer sea surface temperatures in the West Philippine Sea, now about 1.5 degrees Celsius above historical averages, increase evaporation and moisture transport. Topographic amplification further magnifies rainfall as mountain ranges such as the Sierra Madre and Cordilleras force moist air upward, releasing torrential rain over Luzon’s plains. Climate change and ENSO variability add another layer of disruption, delaying Amihan’s onset by two to three weeks compared with the 1980s. Deforestation and watershed degradation exacerbate these effects by reducing the capacity of mountain ecosystems to absorb runoff and help prevent landslides. Rice, the staple crop of the Philippines, is highly sensitive to rainfall variability. Prolonged Habagat seasons increase the risks of lodging, waterlogging, and spoilage. Post-harvest drying also becomes unreliable due to persistent cloud cover and rainfall. Grain moisture levels often exceed the International Rice Research Institute's (IRRI) recommended 14%, affecting storage stability and food quality (IRRI, 2018). Vegetable crops, particularly those grown in Central Luzon, suffer from waterlogging and rot, reducing supply and increasing market volatility. Disaster preparedness is also strained. Flood risks in NCR, Central Luzon, and Northern Luzon remain elevated well into October, putting pressure on urban drainage systems and buffer stock logistics. The late August 2026 floods, which brought more than 300 millimeters of rainfall in three days, illustrate this systemic challenge. This report builds on the study “Habagat and Amihan Variability Affects Food Systems and Disaster Risk Management,” extending its analysis through historical background, scientific explanations, and scenario modeling. By placing current variability within a broader historical and scientific context, the report underscores the need for adaptive agricultural planning, strengthened disaster preparedness, and cooperative governance reforms. The persistence of Habagat into the Ber months is not merely a meteorological anomaly but a systemic challenge requiring action. Without adaptation, the Philippines risks chronic food insecurity, escalating disaster vulnerability, and weakened resilience in the face of climate change. The heavy flooding across Central Luzon and Metro Manila in late August 2026 illustrated the destructive effects of monsoon variability. Rainfall totals exceeded 300 to 400 millimeters in just three days, compared with a volume that historically would have been spread across a month. The Pampanga and Pasig rivers overflowed, while urban drainage systems were overwhelmed by the concentrated rainfall. The flooding reflected the interaction of atmospheric dynamics, ocean warming, topographic amplification, climate change, and ecological degradation. These factors contribute to the persistence of Habagat into the Ber months, turning what was once regarded as a predictable seasonal transition into a prolonged overlap between monsoon systems. The transition between Habagat and Amihan is not a clean handover but an overlapping period. During the intermonsoon period, Amihan’s cooler, denser air masses from Siberia collide with Habagat’s warm, moisture-rich flows from the southwest. Instead of suppressing rainfall, this interaction enhances vertical lifting. Cool