MANILA, Philippines — Sea surface temperatures in the Philippines remained unusually high for three months after the official end of the 2023–2024 El Niño, according to a new study by researchers from the University of the Philippines Marine Science Institute (UP MSI).

The study found that daily sea surface temperatures (SST) peaked at a record-high 30.45°C in June 2024, surpassing levels recorded during previous El Niño events, including the 2015–2016 episode. These elevated temperatures persisted through June to August 2024, well after El Niño ended in May.

Using data from the Global OSTIA NRT dataset, researchers analyzed SST trends from March 2023 to August 2024. The study, titled Evolution of Marine Heatwave in the Philippines During and After the 2023/24 El Niño, was published in the IOP Conference Series: Earth and Environmental Science.

Two waves of marine heatwaves were observed: the first from November 2023 to January 2024 in the northwest Philippines, and the second, more intense one, from April to August 2024 in both northwest and northeast areas. The second group was intensified by warm winds from the southwest monsoon (habagat) as El Niño was ending.

Despite the northeast monsoon (amihan) typically bringing cooler temperatures, it failed to offset the warming caused by El Niño. The heatwaves began in northern regions and gradually moved southward.

The research team included Rachel Francisco, Dr. Charina Lyn Amedo-Repollo, and Chloie Ann Libatog of the Physical Oceanography and Observation Laboratory, along with Dr. Maria Vanessa Baria-Rodriguez of the Interactions of Marine Bionts and Benthic Ecosystems Laboratory.