A key factor driving some of the increasing weather extremes, including coastal flooding, is the world’s warming oceans, said Michael Mann, a climate scientist<\/a> and professor at the University of Pennsylvania. Mann was one of a group of 55 scientists around the world who co-authored an ocean warming study published Jan. 9\u00a0in the journal Advances in Atmospheric Science<\/a>.<\/p>\n 1 \/ 0<\/p>\n High tides break records in January, as wacky weather continues<\/p>\n A resident plays with a dog along a flooded running trail during a king tide in Mill Valley, California on Jan. 5, 2026. The National Weather Service reported record-breaking high tides at several tidal gauges in California, influenced in part by seasonal high tides and higher sea levels.<\/p>\n “Both the warming of the oceans and the ocean surface are playing a role in the extreme weather that we continue to see, as warming oceans evaporate more moisture into the atmosphere, driving the record flooding we are seeing, the more intense and damaging hurricanes, and the melting ice, rising sea level and coastal inundation,” Mann told USA TODAY.<\/p>\n Meanwhile, at least a half-dozen warm temperature records were set on New Year’s Day, according to NOAA’s National Weather Service. The warmth followed a December that broke or tied so many monthly warm high or overnight warm low temperature records that it accounted for nearly 20% of all the monthly warm records set or tied in 2025.<\/p>\n Warm temperature records<\/p>\n Warm temperature records continue to be broken right and left.<\/p>\n In the Sioux Falls, South Dakota, weather service region, a half-dozen new records were set on Jan. 13, the weather service office reported. The 36-degree overnight low temperature at Sioux Falls was 9 degrees warmer than the normal high temperature for the date and 28 degrees warmer than the normal low. At least four other weather stations in the region reported similar overnight lows that were several degrees warmer than the typical high.<\/p>\n NOAA and other leading scientific organizations reported on Jan. 14 that 2025 was the third warmest year on record<\/a> since measurements began in 1850. Each of the last 11 years is among the 11 warmest years on record.<\/p>\n “You\u2019re going to see more warm than cold records, because the climate is getting warmer,\u201d said Alan Gerard, a veteran meteorologist who writes the “Balanced Weather” blog on Substack<\/a>.<\/p>\n Pedestrians walk through floodwaters on Jan. 5, 2026 in Corte Madera, California, when the San Francisco Bay Area experienced unusually high tides that pushed water into low-lying streets.<\/p>\n High tides<\/p>\n Record water levels occurred in some California locations during January’s full moon high tides.<\/p>\n In San Francisco, the tide was the fourth highest since records began in 1898. Record high tides were reported in Santa Barbara, Richmond, Martinez-Amorco and Redwood City. Widespread coastal street flooding occurred in King Salmon and elsewhere along the coast in Humboldt County, California, the weather service said. Flooding also was reported in San Diego.<\/p>\n Federal scientists expect such flooding to become more frequent over time with higher sea levels. NOAA’s annual high tide outlook<\/a> predicts the North Spit location in Humboldt County and San Diego could experience the highest number of flood days along the Southwest Pacific Coast in 2026. Even using the lowest available sea level rise projections, the total number of high tide flooding days in the two locations is forecast to double between 2020 and 2030.<\/p>\n A parking lot floods on Jan. 5, 2026 in Mill Valley, California after high tides in the San Francisco Bay Area.<\/p>\n Warmer oceans<\/p>\n Ocean heat content continued to set records globally in 2025, with “broad ocean warming across basins,” the team of researchers reported in the study Mann participated in. The warming continued “in response to increased greenhouse gas concentrations and recent reductions in sulfate aerosols, reflecting the long-term accumulation of heat within the climate system.”<\/p>\n Monthly and annual changes in heat content in the upper 6,500 feet of the ocean from 1955 through 2025, shown as the difference from the average between 1981 to 2000.<\/p>\n Unlike sea surface temperatures that can fluctuate substantially, ocean heat content \u2013 which measures the warming below the surface of the ocean over the full ocean depth \u2013 shows a very steady warming trend, Mann said. “Though this year was not a new record for global surface temperatures, it was a record for ocean heat content.”<\/p>\n Each of the past nine years has set a new record, Mann said. In 2025, about 33% of the global ocean area ranked among the top three warmest conditions since records began in 1958, while about 57% was within the top five, their study reported.<\/p>\n NOAA reported in a 2025 climate summary that the Antarctic saw its warmest annual temperature on record, while the Arctic annual temperature was the second warmest.<\/p>\n Intense rain<\/p>\n A bevy of scientists have reported the warming oceans also help drive more intense rainfall. That’s especially true for the Gulf of America, renamed from the Gulf of Mexico by President Donald Trump<\/a>, USA TODAY has previously reported<\/a>. The warming Gulf helps move more moisture northward in an arc up and over the central and eastern U.S.<\/a><\/p>\n On Jan. 8, La Farge, Wisconsin, was one of more than a dozen locations within the La Crosse weather service region that set new records for 24-hour rainfalls in the month of January. The 2.29 inches of rain in La Farge was more than an inch above the amount of rain the station normally receives during the entire month.<\/p>\n Dinah Voyles Pulver, a national correspondent for USA TODAY, covers climate change, weather, the environment and other news. Reach her at dpulver@usatoday.com or @dinahvp on Bluesky or X or dinahvp.77 on Signal.<\/p>\n![\"Pedestrians](\"https:\/\/www.newsbeep.com\/us\/wp-content\/uploads\/2026\/01\/88926f633ac13adfb33dd9634fae0226.jpeg\"\/)
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