One of the world’s most important weather forecasts ever made was during the Second World War. Meteorologist, Group Captain James Stagg (attached to the Royal Air Force) persuaded General Eisenhower to change the date of the Allied invasion of Europe from the 5th to the 6th of June 1944 – D-Day. Weather also played a key role in the initial decoding of the complex German Enigma code as code breakers discovered the transmission of coded weather data.
Source: VE Day 75 – Remembering the meteorologists of WW2 | Royal Meteorological Society