Prelude to D-Day: The Weather Forecast that Altered World History

Jun 6, 2025, 11:59 AM

Today is certainly a day of remembrance! I visited Normandy last August. It is surreal. I will never forget seeing the beaches where the Allies changed the future trajectory of the war!

So glad that the greatest generation we have ever seen stood face-to-face with our enemies and kept fighting. I am sure that many of you know this story better than I do. If so, I would love other insights on the final decision to proceed with D-Day. But, it almost didn't happen on June 6, 1944 - and if it didn't happen on June 6, it might not have happened at all.

It is my understanding that not all of his advisors were in agreement. But Eisenhower made the ultimate decision to proceed based on a last-minute weather update.

According to History.com:

“The disappointed commanders knew that the list of potential invasion dates were only a precious few because of the need for a full moon to illuminate obstacles and landing places for gliders and for a low tide at dawn to expose the elaborate underwater defenses installed by the Germans. June 5, chosen by Allied Supreme Commander Dwight Eisenhower to be D-Day, was the first date in a narrow three-day window with the necessary astronomical conditions. The massive Normandy landings, however, also required optimal weather conditions. High winds and rough seas could capsize landing craft and sabotage the amphibious assault; wet weather could bog down the army and thick cloud cover could obscure the necessary air support.

The critical, but unenviable task of predicting the English Channel’s notoriously fickle weather fell to a team of forecasters from the Royal Navy, British Meteorological Office and U.S. Strategic and Tactical Air Force, and as D-Day approached, storm clouds brewed inside the meteorological office.

…

In the early hours of June 4, Stagg believed foul weather was only hours away. He sided with his fellow British colleagues and recommended a postponement. Knowing that the weather held the potential to be an even fiercer foe than the Nazis, a reluctant Eisenhower agreed in the early hours of June 4 to delay D-Day by 24 hours.

On the other side of the English Channel, German forecasters also predicted the stormy conditions that indeed rolled in as Stagg and his fellow Brits had feared. The Luftwaffe’s chief meteorologist, however, went further in reporting that rough seas and gale-force winds were unlikely to weaken until mid-June. Armed with that forecast, Nazi commanders thought it impossible that an Allied invasion was imminent, and many left their coastal defenses to participate in nearby war games.

…

Those weather stations, in particular one at a post office at Blacksod Point in the far west of Ireland, proved crucial in detecting the arrival of a lull in the storms that Stagg and his colleagues believed would allow for an invasion on June 6. As rain and high winds lashed Portsmouth on the night of June 4, Stagg informed Eisenhower of the forecast for a temporary break. With the next available date for an invasion nearly two weeks away, the Allies risked losing the element of surprise if they waited. In spite of the pelting rain and howling winds outside, Eisenhower placed his faith in his forecasters and gave the go-ahead for D-Day.

The weather during the initial hours of D-Day was still not ideal. Thick clouds resulted in Allied bombs and paratroopers landing miles off target. Rough seas caused landing craft to capsize and mortar shells to land off the mark. By noon, however, the weather had cleared and Stagg’s forecast had been validated. The Germans had been caught by surprise, and the tide of World War II began to turn.”

https://www.history.com/articles/the-weather-forecast-that-saved-d-day

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Clemson: Academic Excellence! Athletic Excellence!

They've done a good job in Normandy of maintaining a sense of understanding what happened there - and they are most appreciative for it. The 82nd and 101st Airborne Divisions are legendary there.

Standing on the clifftops and imagining the incredible number of ships that were assembled for the assault forces and looking around at the limited number of German gun emplacements it's easy to see that although machine gun and mortar emplacements were terrible obstacles to the landing troops, the overall advantage was to the landing force - it was overwhelming - particularly without German air superiority.

One of the most incredible successes (to me) was the British glider assault landing to capture "Pegasus Bridge". It was a huge part of the overall operation, which greased the gears for a large part of the invasion. How those glider pilots put those plywood boxes down on the canal banks (in the dark) without colliding with the bridge or going into the water was an amazing piece of bravery and flying skill.

A visit to Normandy is one of the greatest history lessons anyone can ever experience. I spent 13 days visiting as many sites, monuments, churches, cemeteries and museums as I could - but it wasn't enough time to see it all and understand everything that happened there.

Prelude to D-Day: The Weather Forecast that Altered World History

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Did a One-Day Tour. Now Want to Go Back for an Extended Visit

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