Heavy rainstorms in Taiwan claim lives of four individuals within the past week
In late July to early August 2025, Taiwan was hit by an unusual bout of heavy rainfall, causing significant disruptions and losses. The downpours were primarily caused by a low-pressure system, strong southwesterly winds, and monsoon patterns, including the influence of Typhoon Co-May pushing moist air from the South China Sea northwards.
The southwesterly airflow, which typically appears with typhoons or in seasonal rains around May and June, was unusually strong and persistent, producing torrential downpours with over 2 meters of rain in some areas within a week. Meteorologists attribute the heavy rain to changes in the strengthening and weakening of these southwesterly flows above the Bashi Channel, leading to two waves of intense rainfall covering central and southern Taiwan. The rainfall totals reached near-record levels close to those from Typhoon Morakot in 2009, with some areas reporting nearly 3,000 mm (about 3 meters) over the period.
The heavy rain resulted in numerous casualties, with four people killed due to the storms and subsequent floods and landslides. Three people remain missing, and 77 were injured. The disaster has caused widespread damage, with roads damaged and offices shuttered. Nearly 6,000 people were forced to leave their homes, and several thousand more have sought shelter due to the torrential rain.
Taiwan, accustomed to frequent tropical storms from July to October, has not experienced a disaster of this scale before. Premier Cho Jung-tai visited a flood-hit area in the southern Tainan City and stated, "We rarely encounter a disaster of this scale." The average rainfall across the island last month was the highest for the month of July since 1939. The amount of rain is more than Taiwan's annual rainfall of 2.1 meters last year.
The week of bad weather followed Typhoon Danas, which hit Taiwan in early July. The southwesterly winds brought heavy moisture from the South China Sea to Taiwan, leading to the heavy rainfall. Maolin, a district in southern Taiwan, recorded 2.8 meters of rain since July 28.
Regarding the link to climate change, the Central Weather Administration (CWA) stated that this particular event was not directly linked to climate change but rather driven by natural weather systems and typhoon dynamics, especially Typhoon Co-May's effect on regional wind patterns. However, the CWA also noted that the total rainfall for July 2025 was the highest recorded for that month since 1939, highlighting that while this specific event's cause was meteorological, underlying climate factors could influence trends in rainfall intensity over longer periods.
As the rain is expected to ease in the coming days, the government and aid organisations are working to provide support to those affected by the disaster. The focus is on providing shelter, food, and medical assistance to those in need. The people of Taiwan are facing a challenging time, but they are resilient, and the community is coming together to help each other in this difficult period.
Weather forecasting models may have underestimated the intensity of the heavy rain in Taiwan during late July to early August 2025, given the unusual strong and persistent southwesterly airflow induced by Typhoon Co-May. The meteorological agency should research and refine their models to improve weather-forecasting accuracy for such extreme events in the future.
The heavy rain in Taiwan this year, resulting in significant losses and disruptions, serves as a grim reminder of the need for better weather-forecasting, especially considering the increasing frequency and intensity of extreme weather events potentially linked to climate change.
