A woman  and a lighthouse on the north-west coast of County Mayo in the West of Ireland had a huge and unexpected role on the outcome of the Second World War. The weather-monitoring unit at Blacksod Bay Lighthouse, at the southern end of the Mullet Peninsula, had a big influence on the D-Day landings in Normandy, in France, on June 6, 1944.   At that time during the Second World War, most of France was occupied by Hitler’s German army. Weather forecasts from Blacksod Lighthouse on June 3, which had to be repeated three times, showed a sharp drop in atmospheric pressure and the arrival of a storm. They were taken by Maureen Flavin, on her twenty-first birthday, for Ted Sweeney, the lighthouse keeper at Blacksod, the man she would later marry.   A native of Knockanure, County Kerry, Maureen came to Blacksod to work in the local post office. The forecasts were relayed to the UK Meteorological Office in Dunstable, north of London, and carefully considered by the Allied Command.  The readings showed a storm coming over the Atlantic to arrive in Normandy on June 5.  Plans were underway for the biggest seabound invasion in world history on Monday June 5 at full moon and low tide, depending, however, on the weather. Partly because of the adverse weather forecast sent by Edward Sweeney (1906-2001) from Blacksod, the landing did not take place on June 5 as planned.  General Dwight Eisenhower, supreme commander of the Allied cross Channel invasion of the European mainland, considered the opposing weather forecasts from the UK and USA weather forecasters. Good weather was required for the landings and the necessary back-up air support.  Eisenhower took the weather forecast received from County Mayo and decided to delay one of the biggest and important military seaborne operations in world history by one day, when the weather forecast showed a short window as an opportunity. The Normandy landings, known as ‘Operation Overlord’, took place on June 6 1944 on several beaches in Normandy, and their success, together with the heroic role of the Russians in the east, paved the way for the liberation of Europe. 

            Maureen celebrated her hundred birthday in June 2023. In June 2021, the US House of Representatives presented Maureen Sweeney with a special award to recall her special role in world history. Michael D Higgins, President of Ireland, in a letter to her in July 2021 wrote: “Yours is such a story and your legacy a most important and enduring one. Your actions so long ago in Blacksod Bay have had a significant influence on the journey that has brought the world to this contemporary moment”.