James Stagg's Forecast Delayed D-Day

D-Day was originally scheduled for June 5, 1944, but meteorologist James Stagg persuaded Dwight D. Eisenhower to postpone the invasion by one day shortly before it was due to begin. The landings required calm seas, low tides, moderate winds, and a date close to a full moon. Using reports from weather stations across Britain and the Atlantic, along with German U-boat data decoded at Bletchley Park, Stagg's team predicted a brief improvement on June 6. The troops still faced strong winds and choppy seas, but the narrow weather window allowed the invasion to proceed.

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