David Hosler was going through his father’s files last fall when he came across a copy of James A. Michener’s Pulitzer Prize–winning story collection Tales of the South Pacific. When Hosler picked up the book, a postcard slid from its pages.

“It says something like, ‘Dear Charlie, thank you so much for helping me with this. … I cannot thank you enough,’” Hosler recalls. “He had all these giant file cabinets and boxes—I’m talking 700 pounds of paper—and it was full of things like that.”

Those files brimmed with the tangible evidence—presidential commendations, awards and plaques from academic and scientific organizations, personal notes from luminaries in science, politics, and the arts—of Charles Hosler’s life. Signs of his legacy have long been widely visible at University Park, where the former Mineral Sciences Building was renamed in his honor in 1994 and an iconic oak tree at The Arboretum bears his name. His broader influence on the field of weather forecasting might seem less obvious, but it’s felt indirectly by billions of people around the globe every day.

Hosler ’47, ’48 MS, ’51 PhD EMS, an adviser to U.S. presidents, mentor to future leaders in the science and business of forecasting, and longtime Penn State professor and administrator who spent two decades as dean of the College of Earth & Mineral Sciences, died on Oct. 29, 2023. He was 99.

“He truly was curious about everything in the world,” David Hosler says of his father. “He taught all of his students to have that curiosity and love of knowledge, and to apply what they were learning in a way that applied not only to research, but to the greater world.”

Charles Hosler was born in 1924 in tiny Honey Brook, Pa., about 50 miles northwest of Philadelphia. One of three children, he was 5 when the Depression hit; David Hosler recalls his father telling the story of selling watercress sandwiches door to door as a child. “It was abject poverty,” David says. “Because of that, he always worked extremely hard.”

A teacher’s encouragement convinced Hosler’s parents to send him to off to college in 1942, a reach they could afford only by taking out a $200 loan—one that Hosler himself later repaid with his earnings from the Navy. As for so many of his generation, the arrival of World War II brought both upheaval and opportunity. Putting college on hold, Hosler joined the service and was sent to the Pacific, where he was stationed for a time on Guam and assigned to weather observation flights. Interviewed by Weather World in 2010, Hosler recalled flying 12 to 14 hours a day, watching the patterns of the waves and encountering the occasional typhoon. “We wound up lots of times in the eye of a storm,” he said. “We never came back with all four engines, but we never came back with less than two. That’s how I got into meteorology.”

After the war, he finished his undergraduate meteorology degree, followed quickly by master’s and doctoral degrees in the department that would soon bear his imprint. When he joined the meteorology faculty—then comprising just three members—“state of the art” forecasting relied purely on surface and balloon observations, and few took it seriously as science. But Hosler, long before the proliferation of computer modeling and satellite technology, saw the potential—and value—of careful observational science. “He had so many insights about observing the atmosphere that weren’t proven for 15 or 20 year, but turned out to be right,” says Joel Myers ’61, ’63 MS, ’71 PhD EMS, a graduate student of Hosler’s and founder of the global forecasting giant AccuWeather.

Myers was among those who went on to success as innovators in industry; others have led organizations such as the National Weather Service and National Oceanic and Atmospheric Administration; and still others followed his lead and stayed in academia. Hosler joined the meteorology faculty as a professor in 1951, was department head from 1961 to 1965, and EMS dean from 1965 to 1985. Inspired in part by a conversation with the manager of an Altoona TV station who admitted that its weather forecast was entirely made up, Hosler created one of the first television weather shows, which featured weather maps drawn on a chalkboard and was broadcast from Sparks Building when it debuted in 1957. The show, later dubbed Weather World, has provided dozens of future meteorologists with their first broadcast experience.

“He said he got frustrated listening to local forecasts and thinking, ‘Where the heck did they get that?’” says Jon Nese ’83, ’85 MS, ’89 PhD EMS, a meteorology professor and longtime Weather World host. “He was motivated to do more forecasting and to communicate the forecast, and he believed that this was something Penn State should be doing.”

Hosler’s former students, and the students whom those students trained and mentored, are the visible legacy of the program he’s chiefly responsible for building. Less obvious is the work he did behind the scenes to build Penn State’s research prowess; as Myers says, “He knew, practically, how to get things done.” In that, Hosler’s relationship with a former university president proved particularly worthwhile: Milton Eisenhower, who led Penn State from 1950 to 1956, was an exceptionally close adviser to his brother, U.S. President Dwight Eisenhower. “Charlie once told me, ‘It never hurts for the president to know who you are,’” Nese says. “I took it to mean he was talking about both of them.”

If having Milt’s ear was good, earning Ike’s trust was invaluable. Hosler did just that in 1955, when Eisenhower arrived from Washington to deliver the commencement speech. There was rain in the forecast that June Saturday, and at one point Eisenhower was advised against giving the speech at Beaver Field, where the crowd would have no protection from the skies. Then Hosler was consulted. He told the president that there should be a window of a few rain-free hours that would allow him to deliver his speech. Sure enough, the rain held off when Ike spoke. Hosler later joked that he got lucky, but no matter. “He was enamored with my forecast,” Hosler said in that 2010 interview, “and as a result, he never went anywhere without calling me to make sure the weather was OK. That was good for our program.”

Hosler later developed a great friendship with President Jimmy Carter, who visited Central Pennsylvania on fly-fishing trips, and he remained an adviser to former students, from Myers at AccuWeather to the heads of government agencies who relied on his wisdom and instincts. After retiring as EMS dean, Hosler served as senior vice president for research and dean of the graduate school from 1985 to 1992, and as executive vice president and provost from 1990 to 1991, before officially retiring in 1992. A Penn State Distinguished Alumnus, he was elected to the National Academy of Engineering, and served on the National Science Board and as president of the American Meteorological Society.

The documentation of all that recognition ended up with the rest of his papers, boxes of history left for others to appraise. His legacy lives on in his students and the generations who’ve followed, the visionary forecasters working to see as far into the future as they can.