Lawrence Hogben

Map adapted from Ludovic Kennedy’s ‘Pursuit’ (1974).

Sixty years ago, on Sunday, 18 May 1941, Admiral Lutjens took the battleship Bismarck, the pride of the German Navy, out to sea from Gdynia in the Gulf of Danzig, along with the heavy cruiser Prinz Eugen. His mission was to sink as many ships of the vital Atlantic convoys as possible. He hoped to skirt the Norwegian...

‘Everything on the Normandy beachhead will hang on your weather,’ said the D-Day planners, assuming that we meteorologists had total control of the elements. ‘Just name us five fine, calm days and we’ll go.’ A hundred years of weather records suggested there was no hope of their getting this. They limited their demand to ‘a quiet day with not more than moderate winds and seas and not too much cloud for the airmen, to be followed by three more quiet days.’ On top of this, the military insisted on a late full moon for the parachutists, plus a tide that would be high three hours after pioneer forces had landed at dawn to clear paths through the beach mines and other obstacles. Tides and moon being fully predictable, they would determine possible dates. July would be too late, and May too early. That left just four possible days: 5, 6, 19 or 20 June. We worked out the odds on the weather on any one of these four dates conforming to requirements as being 13 to one against. So meteorologically, D-Day was bound to be a gamble against the odds.