Monthly Archives: June 2026

D-Day was the name given to the June 6, 1944, invasion of the beaches at Normandy in northern France by troops of the Allied Forces during World War II. The goal was to cross the narrow, often stormy, English Channel into Nazi-occupied France.

The successful D-Day invasion required a combination of environmental factors: initial invasion around sunrise and at at low tide; nearly clear skies; at least 3 miles of visibility; close to a full moon; relatively light winds; non-stormy seas; and good conditions persisting for at least 36 hours and preferably for four days. To make the task of forecasting even more difficult, the Allies needed at least two days advance notice of these conditions —and because the science of meteorology was only just beginning to modernize, at the time this was a nearly hopeless task. Continue reading →