The Pacific Ocean is experiencing one of the largest marine heatwaves on record in 2025, with unusually warm conditions extending from East Asia to the U.S. West Coast. This large patch of above-normal ocean temperatures — often called “the Blob” — now stretches roughly 5,000 miles across the North Pacific, and scientists are observing sea surface temperatures that have smashed long-standing records. Japan experienced its hottest summer on record in 2025, with inland temperatures reaching about