Clues about the possible reemergence of the Blob – a recurring Pacific marine heatwave – can be seen in this summer’s global ocean data. The Blob is a swarming mass of warm water in the North Pacific Ocean. Surface air temperature anomaly for the boreal summer from June to August 2025 relative to the average for 1991-2020: note the red patch over the North Pacific. In 2019, another surge in Pacific Ocean temperatures was recorded, prompting some to dub it “The Blob 2.0”. This year, the strange marine heatwave appears to be further across the North Pacific, spanning from Alaska's Aleutian Islands to the coast of East Asia.