Maureen Sweeney, weather watcher who influenced D-Day plans, dies at 100

Ms. Sweeney’s weather data from western Ireland offered the first clues of a major storm, leading to a one-day delay in the D-Day invasion in 1944

By Brian Murphy
December 20, 2023 at 8:35 p.m. EST


Maureen Flavin and Ted Sweeney on their wedding day in 1946. (Courtesy of Fergus Sweeney)

Before dawn on June 3, 1944, a postal clerk in Ireland’s County Mayo checked her weather gauges. A storm was coming fast. The barometer readings were dropping. The wind, pouring off a low-pressure zone in the mid-Atlantic, was slicing through the drizzle in the village of Blacksod.

She double-checked the observations. They then were passed along until finally they reached Britain’s Met Office, which since 1939 had used the Blacksod post office as one of its weather stations. Blacksod carried particular importance. Its position on Ireland’s northwestern coast was often an early warning of Atlantic weather systems headed for Britain.

The data collected that morning was the most significant yet. About 7,000 ships and landing craft, 11,000 aircraft and more than 130,000 Allied troops were amassed for Operation Overlord, the invasion into Nazi-occupied France. The only missing puzzle piece was the weather forecast for the English Channel to decide if June 5 would be D-Day.

The storm observations from County Mayo were the first indications of trouble ahead. The invasion was postponed until June 6. And the postal worker — 21-year-old Maureen Flavin — became part of World War II lore as a linchpin in the weather team whose work persuaded commanders to hold off for 24 hours the air-and-sea assault that helped change the course the war.

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The weather station and post office in Blacksod, Ireland, in the 1940s. (Courtesy of Fergus Sweeney)

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The Blacksod lighthouse was Maureen Sweeney's home from the 1940s until the mid-1970s. It's at the southern end of the Mullet Peninsula in County Mayo, Ireland. (Courtesy of Fergus Sweeney)

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Gen. Dwight D. Eisenhower speaks to paratroopers in England just before the first assault in the D-Day invasion on June 6, 1944. (AFP/Getty Images)

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By Brian Murphy
Brian Murphy joined The Washington Post after more than 20 years as a foreign correspondent and bureau chief for the Associated Press in Europe and the Middle East. Murphy has reported from more than 50 countries and has written four books. Twitter https://twitter.com/BrianFMurphy

Maureen Flavin Sweeney Dies at 100; Her Weather Report Delayed D-Day
She helped save General Eisenhower’s invasion from potential disaster, enabling the Allies to gain a foothold in France that was essential to victory in World War II.


Maureen Flavin Sweeney became part of World War II lore after her weather report persuaded commanders to delay the D-Day invasion for 24 hours. She is pictured with her husband, Ted, on their wedding day in 1946. via Fergus Sweeney

By Alex Traub
Published Jan. 2, 2024
Updated Jan. 3, 2024

On certain rare occasions, ordinary people in the midst of an average day have changed history. ... In 1947, Muhammad edh-Dhib, a young Bedouin shepherd looking for a sheep gone astray, discovered a hidden cave that contained the Dead Sea Scrolls, the earliest known version of most of the Hebrew Bible. Making his rounds one night in 1972, Frank Wills, a Washington, D.C., security guard, noticed a piece of tape holding a lock open in a building where he worked — and as a result he exposed the Watergate break-in, ultimately leading to the resignation of President Richard M. Nixon.

But neither of them shaped as many lives as directly as Maureen Flavin, a postal clerk on a remote stretch of the northwest Irish coast who, in 1944, on her 21st birthday, helped determine the outcome of the Second World War. ... She died on Dec. 17 in a nursing home in Belmullet, Ireland, near the post office where she used to work, her grandson Fergus Sweeney said. She was 100. ... The events that led Ms. Flavin to her unforeseeable moment of global consequence began in 1942 when she saw an ad for a job in the post office of the remote coastal village of Blacksod Point.

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On her 21st birthday, June 3, she had a late-night shift: 12 a.m. to 4 a.m. Checking her barometer, she saw that it registered a rapid drop in pressure, indicating a likelihood of approaching rain or stormy weather. ... The report went from Dublin to Dunstable, the town that housed England’s meteorological headquarters. ... Ms. Flavin then received an unusual series of calls about her work. A woman with an English accent asked her: “Please check. Please repeat!”

Ms. Flavin asked the postmistress’s son and Blacksod’s lighthouse keeper, Ted Sweeney, if she was making a mistake. ... “We checked and rechecked, and the figures were the same both times, so we were happy enough,” she later told Ireland’s Eye magazine. ... That same day, Eisenhower and his advisers were meeting at their base in England. James Stagg, a British military meteorologist, reported that, based on Ms. Flavin’s readings, bad weather was expected. He advised Eisenhower to postpone the invasion by a day. ... The general agreed. June 5 saw rough seas, high winds and thick cloud cover. Some commentators — including John Ross, the author of “Forecast for D-Day: And the Weatherman Behind Ike’s Greatest Gamble” (2014) — have argued that the invasion could well have failed if it had occurred that day.

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A correction was made on Jan. 3, 2024: An earlier version of a picture caption with this obituary misstated the rank of the British Army officer Bernard Montgomery in June 1944, when the photograph of him with Gen. Dwight D. Eisenhower was taken. He was a general but not yet field marshal.

When we learn of a mistake, we acknowledge it with a correction. If you spot an error, please let us know at nytnews@nytimes.com.Learn more
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Alex Traub works on the Obituaries desk and occasionally reports on New York City for other sections of the paper. More about Alex Traub