A month-by-month look at the events leading up to D-Day, 6 June 1944
September: The Second World War begins as Britain and France declare war on Germany following Germany’s invasion of Poland. Poland’s defeat by Germany is followed by the “Phoney War” over the winter of 1939-1940, as neither Germany nor Britain/France launches a major attack.
May – June: German invasion of France, Belgium, Holland, Norway and Denmark. These countries are rapidly defeated by Germany after offensives known as “Blitzkrieg” (meaning “lightning war”, due to the speed of the attacks).
June – September: During the Battle of Britain, Germany’s air force (the Luftwaffe) tries and fails to dominate the British Royal Air Force (RAF). The RAF’s defeat would have enabled the Germans to invade Britain.
August 1940 – May 1941: The Blitz – Unable to launch an invasion by sea, Germany conducts a series of heavy bombing attacks on Britain’s cities.
June: Germany invades her former ally the Soviet Union (which consequently becomes Britain’s ally). This begins the bloody struggle on the Eastern Front, which continues until the end of the war in 1945.
December: Japan attacks the US fleet at Pearl Harbour, inflicting serious damage and involving the US directly in the Second World War. Germany declares war on the USA, bringing American into the war in Europe. At the Washington Conference, Britain and the US agree a strategy of “Europe first” – in other words, that they will concentrate on the defeat of Germany before turning to deal with Japan. This begins the train of events that would lead to D-Day.
April: The build-up of US forces in Britain (Operation Bolero) begins, in preparation for D-Day.
August: The Allied raid on the French coastal town of Dieppe (using mainly Canadian troops) is repulsed with heavy casualties. The raid graphically illustrates how difficult the Allied invasion of Europe would be.
October – December: The critical Allied victories that will lead to the defeat of Axis (German and Italian) forces in North Africa – The Battle of El Alamein is won by the British Eighth Army under General Montgomery; American/British forces land in Morocco and Algeria, commanded by General Eisenhower.
January: At the Casablanca Conference, the Allies agree that the conditions are not right for D-Day to take place in 1943. Instead, the Allies will capture Sicily. They decide to form an Anglo-American staff to begin the detailed planning for D-Day.
March: The Anglo-American staff is formed under the command of British Lieutenant General Morgan. He is given the title of COSSAC (Chief of Staff, Supreme Allied Commander). The Supreme Allied Commander has not yet been appointed.
July and September: The Allied landings in Sicily and mainland Italy respectively lead to the Italian surrender, and open a new front in the war in Europe.
August: At the Quebec Conference, the Allies adopt COSSAC’s outline plan for D-Day.
October: British Admiral Sir Bertram Ramsay is appointed as the Allied naval commander for D-Day.
November: The British, American and Soviet leaders – Winston Churchill, Franklin Roosevelt and Joseph Stalin – meet together for the first time, at the Teheran Conference. Stalin urgently wants to know when the Allies will land in France, to aid the Soviet armies fighting on the Eastern Front. Churchill and Roosevelt tell him that the planned date is May 1944. Discussions are also held on related matters, such as the planned Allied landings in the south of France (in the event, these will take place in August 1944).
December: Field Marshal Erwin Rommel is given responsibility for improving the German defences on the French coast, which the Allies will have to overcome on D-Day (including minefields, obstacles to sink landing craft, and pillboxes). He is later appointed commander of the German Army Group B in France. Construction work also begins at various points along the English coasts, in this case however on the first sections of the Mulberry Harbours. These artificial harbours, made in huge sections from steel and concrete, will be towed over to Normandy after D-Day and assembled there. They will enable the Allies to land troops and equipment at a faster rate than is possible straight onto the beaches. Also, after months of indecision on the part of the Allied leaders, US General Dwight D. Eisenhower is finally appointed as Supreme Allied Commander, in overall charge of Operation Overlord (the D-Day landings and subsequent fighting in Normandy). General Bernard Montgomery (“Monty”) is appointed to command 21st Army Group, with responsibility for the assault landings on D-Day and the following ground fighting. Earlier in the war, he had fought – and beaten – Rommel’s forces in North Africa.
January: With the new year, the planning for D-Day takes on greater urgency. The newly appointed Allied commanders begin revising the draft plans that had been drawn up by COSSAC. In particular, they decide that the number of troops to be landed in the first waves on D-Day needs to be considerably increased. Further naval forces and aircraft must therefore be found to support these additional troops. The target date for D-Day is moved from 1 May to 31 May, to allow time for these preparations. Midget submarines of the Combined Operations Pilotage Parties (COPP) secretly visit the Normandy beaches to take sand samples. These are needed to confirm that the sand on certain sections of the chosen landing beaches will support the weight of the tanks that the Allies plan to land on D-Day. Across many parts of Europe, including France, British and US aircraft begin to drop weapons and supplies to the Resistance. This will enable them to fight back against the occupying Germans. Back in the UK, the first amphibious exercise for American troops takes place at Slapton Sands, Devon. The exercise involves 16,000 assault troops, and is a rehearsal of the techniques that will be used on D-Day itself.
February: Over a long period, Allied air forces (RAF Bomber Command, and the United States Army Air Force’s 8th Air Force) have been making a series of heavy air raids against German cities. German fighter aircraft defend against these attacks, and there are heavy casualties on both sides in this aerial fighting (and many German civilians are also killed). The Germans are less able to replace these losses of airmen and aircraft than the Allies. As a result, by the time of D-Day the German air force will not be strong enough to oppose the Allied landings in France. In response to these attacks, the Germans begin a series of bombing raids on the UK, known as the “Little Blitz”. They are less intense than the Blitz of 1940 – 1941 and last until March, although the worst attacks are during February. Meanwhile, back in the UK, the training and preparations for D-Day continue.
March: The Allied headquarters for D-Day (SHAEF, or Supreme Headquarters Allied Expeditionary Force) moves from Norfolk House in central London to Bushy Park, on the western outskirts of the capital. It has grown too large for Norfolk House, and the Supreme Allied Commander (General Dwight D. Eisenhower) felt it necessary to move away from the distractions of London. On 6 March, Allied air forces carry out the first of many raids on the French railway network. This is part of the Transportation Plan, which aims to reduce the Germans’ ability to use the French railways to transport troops and military supplies. After many months of debate, the Combined Chiefs of Staff (the American and British heads of the armed forces) decide to delay the planned landings in the South of France. These landings, codenamed Operation Dragoon, had originally been planned to take place simultaneously with D-Day, so that the German troops in France would be attacked from two directions. However there were insufficient Allied ships available to launch both invasions at once. For the Allied forces, planning and training continues.
April: At the start of the month, a 10-mile strip along much of Britain’s coastline becomes a restricted zone. Civilians living outside the zone are forbidden from entering it, and those inside cannot leave. The Royal Navy begins a campaign of mine-laying off German bases along the Channel coast. These minefields were intended to prevent the fast German motor torpedo boats (known as E-Boats) from coming out to attack Allied shipping. The Allied commanders and their staffs have completed the overall plan for D-Day. Now, the less senior officers in charge of the actual units (brigades, regiments and battalions) that will land on the beaches early on D-Day begin to draw up plans. For the vast majority of troops, however, it will be at least a month before they know when and where the invasion will take place. Early in the morning of 28 April, US forces taking part in a major training operation, Exercise Tiger, are intercepted by German E-Boats. The attack takes place off Slapton Sands, Devon, and over 600 US soldiers and sailors are killed. Three of the valuable LSTs (LST stands for Landing Ship, Tank) are sunk or badly damaged – each could carry up to around 70 vehicles, so their loss is serious. The ships attacked are part of Force U, which on D-Day will land troops on Utah Beach. At the end of the month, Admiral Sir Bertram Ramsay, the Allied naval commander, moves his headquarters to Southwick House, just north of Portsmouth. Next month, many of the other Allied commanders and headquarters will also move into this area.
May: The month before D-Day.
2 May: The date for D-Day is delayed from 31 May. Two periods in the following month are identified as suitable, based on the tides and the amount of moonlight: 5-7 June and 18-20 June. Later in May, 5 June is chosen as the target date for the D-Day landings.
2 May: Exercise Fabius begins at several sites along the coast of southern England. This is the largest series of training exercises so far, and the last before D-Day. In total, 25,000 troops land at a number of different beaches: the US 1st and 29th Divisions at Slapton Sands; the British 50th Division at Hayling Island; the Canadian 3rd Division at Bracklesham Bay; the British 3rd Division at Littlehampton. The exercises last until 8 May.
15 May: The final briefing for Allied senior officers takes place at St Paul’s School, London. It is attended by King George VI and Prime Minister Winston Churchill.
By now, the troops that will land in Normandy on D-Day and immediately afterwards are in camps all along the south coast of England. Before the end of May, the troops are sealed in the camps, to guard the secret that the landings are imminent. Vehicles and other equipment are waterproofed, to ensure that they can wade through deep water when landing on the beaches. In the last days of May, the troops are briefed on their tasks for D-Day. The majority still do not know exactly where the landings will take place, however.
31 May: The first troops begin to load onto the ships and landing craft that will take them to Normandy. The size of the landing force means that the embarkation process is spread over five days.
June: The Normandy Landings begin
1 June: Eisenhower moves his HQ to Southwick House, just north of Portsmouth. There is a security scare when, for the fifth time in a month, one of the D-Day codenames appears as a crossword clue in the Daily Telegraph – in this case “Neptune”, the code for the naval assault crossing. It turns out that this is just a bizarre coincidence: a Surrey school headmaster compiled the crosswords months ago. In the evening, the first part of a poem by Paul Verlaine is broadcast by the BBC: “Les sanglots lourds/Des violons de l’automne…” (“The heavy sobs of autumn’s violins…”). This is a coded warning message for the French Resistance relating to plans to carry out railway sabotage (not a general message to the Resistance, as is sometimes said) and meant that the invasion would take place within one month. The Abwehr (German military intelligence) intercepts the message and is also aware of its significance.
2 June: The first part of the invasion fleet sets off for Normandy: two Royal Navy X-craft (mini-submarines). They arrive off the Normandy coast the next day, and will stay there submerged until D-Day, when they will surface to guide in the first Allied craft at Juno and Sword beaches. The bombardment warships, which will shell the German defences on D-Day, begin to leave their ports at Scapa Flow, Belfast and the Clyde.
3 June: Early in the morning, the chief allied weather forecaster, Group Captain James Stagg, predicts bad weather for D-Day (at this point, the chosen date is still 5 June). The forecast has not improved by the evening: low cloud, strong winds and rough seas. Winston Churchill visits Southampton, Portsmouth and Southwick House. US airborne troops are briefed for D-Day – they are now told that they are going to Normandy. Most other troops do not yet know.
4 June: At 4.15 a.m., the Allied commanders meet again to consider the weather forecast, and decide to postpone the invasion, which would otherwise take place the next day. Ships already at sea are recalled. Erwin Rommel, the German commander in Normandy, returns to Germany for his wife’s birthday. He plans to return on 8 June, and believes that the weather is too bad for the Allies to land in the meantime. In the afternoon, an Associated Press report announces that the invasion has begun! A teletype operator is practising and doesn’t realise the machine is connected. The news is then broadcast around the world, until Associated Press issues a correction five minutes later. In the evening, the Allied forecasters predict a 36-hour break in the weather, and it seems possible that D-Day can be on 6 June.
5 June: At 4.15 a.m., the Allied commanders meet one final time to hear the weather forecast. The forecast is good, and D-Day will definitely be on 6 June. A few hours later, Allied junior officers begin to open their sealed orders and find out the location of the landings. Black and white stripes are painted on all Allied aircraft, for recognition purposes. The first troop convoys leave England’s south coast ports. General Eisenhower watches the troops embarking at Portsmouth in the morning, and then in the evening visits the US 101st Airborne Division near Newbury, only hours before they leave for France. At 8.15 p.m., the second half of Verlaine’s poem (“Bercent mon coeur/D’une langeur monotone – “sooth my heart with a monotonous langour”) is broadcast by the BBC as a coded message to the French Resistance. The German military intelligence service (the Abwehr) is aware of the message’s significance and also hear it. They pass an invasion alert on to various headquarters, including that of the German 15th Army (based in northern France). However the German 7th Army in Normandy is not alerted. In any case, German commanders had received a number of invasion alerts over recent months, and this seemed to them to be just another false alarm. At about 11 p.m., the British and American airborne troops begin taking off from bases in England. They will be the first Allied soldiers to land in Normandy, by glider and parachute, in the early hours of the following morning.
6 June: D-Day! The first troops land just from the air after midnight. British airborne troops capture the bridges at Benouville (Pegasus Bridge) and Ranville to the east of the landing beaches, while on either side of the beaches, British and US airborne pathfinders parachute in to mark the drop zones for their comrades, due to arrive over the next hours. Within about six hours, the first troops will be landing on the beaches. This is the 1738th day of the Second World War.
Main published sources:
Anthony Hall, Operation Overlord: D-Day Day by Day (Grange Books, 2003)
Cesare Salmaggi & Alfredo Pallavisini, 2194 Days of War (Windward, 1979)
David Stafford, Ten Days to D-Day (Little, Brown, 2003)
Peter Young, The Almanac of World War II (Hamlyn, 1981)