Mr. Hendrickson observes a storm in the 1930s. (D.L. Hendrickson)

Every day in the century that Richard G. Hendrickson spent on Hill View Farm, a poultry and dairy operation in the Long Island hamlet of Bridgehampton, N.Y., there were duties to be done.

There were eggs to collect — 4,500 a day when he was young. There were cows to milk. There was hay to cut. And there was the temperature, maybe even some rainfall, to measure, a task that he faithfully performed twice a day, morning and evening, during an unprecedented 85 years as a National Weather Service volunteer.

Officially, Mr. Hendrickson, who died Jan. 9 at 103, belonged to the Weather Service’s corps of Cooperative Observers, a network established in 1890 to help track meteorological data across the expanse of the United States. The group today includes more than 8,700 volunteers.

Mr. Hendrickson was the first observer in the program’s history to serve more than 80 years, a distinction that made him a celebrity among the country’s most devoted weather buffs. The Weather Service, an authority in the measurement of accumulation, estimated that Mr. Hendrickson had compiled more than 150,000 weather observations in his life.

He did not set out to be a weatherman, volunteer or otherwise. In his teens, a period that coincided with the Calvin Coolidge administration, he befriended a local writer and weather enthusiast who asked to install a weather observation station on the Hendrickson farm. The family agreed, Mr. Hendrickson became an apprentice, and by July 1, 1930, according to many accounts, he had taken over its operation.

Mr. Hendrickson demonstrates his method of collecting data for the National Weather Service in 2014. (AP)

The weather station, resembling a miniature white shed on stilts, contained thermometers to measure the high, low and current temperatures. Mr. Hendrickson’s instruments also included a rain gauge and a wind gauge, installed on his roof, which he checked during storms as frequently as every quarter-hour.

Most modern-day Cooperative Observers submit their findings electronically. Mr. Hendrickson used a black rotary phone. The New York Times, reporting in 2014 on the milestone of his 84th year as a weather volunteer, described the daily routine:

“Bridgehampton,” he would announce to the meteorologist on duty at the regional forecast office. “Good morning.”

Mr. Hendrickson also produced a regular written chart and report, submitted in carbon copy to the Weather Service, its predecessor, the U.S. Weather Bureau, and several local newspapers, in which he spun his observations of the skies into poetic meditations on the joys and agonies of the farmer’s life.

“Pastures burnt brown,” he wrote in an Aug. 26, 1948, installment excerpted by Newsday. “Poultry farms lost hundreds of birds from heat. All sweet corn, cucumber dried up. Feed corn drying fast.”

Winter, too, brought its threats. “If ever you were to feed the wildlife,” he wrote in January 1965, “it is now. It is impossible for the birds and rabbits to dig through the settled, hardpacked and frozen 6 inches of crusty snow to get seeds and food.”

But on occasion, the sky offered some reward, such as in October 1974, as reprinted in Newsday:

“At month’s end,” Mr. Hendrickson reported, “each night a most beautiful ‘Hunter’s Moon’ rose in splendor that has awed civilization since history began.”

The Weather Service describes the Cooperative Observer network as “the most definitive source of information on U.S. climate trends for temperature and precipitation,” providing data that are “invaluable in learning more about the floods, droughts, heat and cold waves affecting us all.”

Mr. Hendrickson sought no remuneration for his data collection, not even during the Depression, when he said his family fell into debt for its chicken house and farmhouse. A farmer must be his own weatherman, he once told the Associated Press, because “you don’t cut hay today and let it dry in the field if you know it’s going to rain tomorrow.”

Plus, “it’s what I do for my country,” Mr. Hendrickson told Newsday in 1997. “I don’t belong to the fire department. I’ve got to do something.”

Richard Grainger Hendrickson was born Sept. 2, 1912, in the farmhouse on Hill View Farm. From a young age, he was attuned to the rhythms of nature.

“I’d come out at night and hear an owl hoot, I’d hear a fox bark, I’d hear a farmer’s dog bark because maybe a rabbit hopped too close to him,” he told the Times. “I’d look up and see the stars, and I’d see rings around the moon.”

He left high school to work on the farm and later trained in animal husbandry through a program of Cornell University in Ithaca, N.Y.

He experienced perhaps the most severe weather calamity of his life in 1938, when a massive hurricane struck the East Coast. The storm drowned 4,000 of the farm’s chicks and knocked down but did not destroy Mr. Hendrickson’s weather instruments.

“I set them back up again and put longer stakes in the ground, the legs on the shelter,” Mr. Hendrickson told the Times, “and went and milked the cows.”

Mr. Hendrickson retired from farming in the early 1980s and sold the farm and much of his land in 1999. He continued as a Cooperative Observer until last year. A wireless weather station has been installed as a substitute for the one he tended, according to a granddaughter, Sara Hendrickson. She said her grandfather died at a care center in Westhampton, N.Y., and that the causes were dementia and pancreatic cancer.

Only rarely in his 103 years did Mr. Hendrickson take a break from his farming or meteorological responsibilities. Once, he won a trip to New Zealand. He did not depart without arranging for family members to take the daily weather measurements in his absence.

His first wife, the former Dorothea Haelig, died in 1982 after more than four decades of marriage, and their son, Richard H. Hendrickson, died in 2014. Mr. Hendrickson’s second wife, the former Lillian Boldak, died in 2015 after more than 30 years of marriage. Survivors include a sister and three granddaughters.

Mr. Hendrickson wrote a book, “Winds of the Fish’s Tail” (1996), on the history of weather on Long Island. Few if any experts knew more about the topic than he did. But even Mr. Hendrickson acknowledged the existence of some weather phenomena too extraordinary to be measured.

“There aren’t words that can tell you the beautiful condition of the sky,” he told the Times, reflecting on a sunset.