1940

A calendar from 1940 according to the Gregorian calendar, factoring in the dates of Easter and related holidays, cannot be used again until 5280.

Events Below, events related to World War II have the "WWII" prefix.

January

January 4 – WWII: Luftwaffe Chief and Generalfeldmarschall Hermann Göring assumes control of most war industries in Germany, in his capacity as Plenipotentiary for the Four Year Plan. January 6 – WWII: Winter War – General Semyon Timoshenko takes command of all Soviet forces. January 7 – WWII: Winter War: Battle of Raate Road – Outnumbered Finnish troops decisively defeat Soviet forces. January 8 – WWII: Winter War: Battle of Suomussalmi – Finnish forces destroy the Soviet 44th Rifle Division. Food rationing in the United Kingdom begins; it will remain in force until 1954. January 9 – WWII: British submarine is sunk in the Heligoland Bight. January 10 – WWII: Mechelen incident – A German plane carrying secret plans for the invasion of Western Europe makes a forced landing in Belgium, leading to mobilization of defense forces in the Low Countries. January 19 – The Three Stooges' You Nazty Spy!, the first Hollywood anti-Nazi comedy film, is released. January 27 – WWII: A peace resolution introduced in the Parliament of South Africa is defeated 81–59. January 29 – Three gasoline-powered trains carrying factory workers crash and explode while approaching Ajikawaguchi Station, Yumesaki Line (Nishinari Line), Osaka, Japan, killing at least 181 people and injuring at least 92.

February

February 2–11 – Scheduled dates for the 1940 Winter Olympics in Garmisch-Partenkirchen, Germany, cancelled in November 1939 due to WWII (originally allocated to Sapporo, Japan). February 1 – WWII: Winter War – Soviet forces launch a major assault on Finnish troops occupying the Karelian Isthmus. February 15 – Paul Creston's Saxophone Sonata is officially premiered at the Carnegie Chamber Hall by saxophonist Cecil Leeson, who had commissioned it from the composer. February 16 – WWII: Altmark incident – British destroyer pursues German tanker Altmark into the neutral waters of the Jøssingfjorden in southwestern Norway and frees the 290 British seamen held aboard. February 22 – In Tibet, province of Ando, 4-year-old Tenzin Gyatso is proclaimed the tulku (rebirth) of the 13th Dalai Lama. February 27 – The radioactive isotope carbon-14 is discovered by Martin Kamen and Sam Ruben at the University of California, Berkeley. February – The last mounted charge by a British cavalry regiment is made when the Royal Scots Greys are called to quell Arab rioters in Mandatory Palestine.

March

March 5 – Katyn massacre: Members of the Soviet Politburo (Joseph Stalin, Vyacheslav Molotov, Lazar Kaganovich, Mikhail Kalinin, Kliment Voroshilov and Lavrentiy Beria) sign an order, prepared by Beria, for the execution of 25,700 Polish intelligentsia, including 14,700 Polish POWs. March 11 – Ed Ricketts, John Steinbeck and six others leave Monterey, California, United States, for the Gulf of California, on a marine invertebrate collecting expedition. March 12 – Moscow Peace Treaty: The Soviet Union and Finland sign a peace treaty in Moscow, ending the Winter War; Finns, along with the world at large, are shocked by the harsh terms. March 13 – Indian nationalist Udham Singh assassinates Sir Michael O'Dwyer (in revenge for the 1919 Jallianwala Bagh massacre) at Caxton Hall in London, for which he is hanged on 31 July at HM Prison Pentonville. March 18 – WWII: Axis powers – Adolf Hitler and Benito Mussolini meet at Brenner Pass in the Alps. After being informed by Hitler that the Germans are ready to attack in the west, Mussolini agrees to bring Italy into the war in due course. March 21 – Édouard Daladier resigns as Prime Minister of France; Paul Reynaud succeeds him. March 23 – Pakistan Movement: The Lahore Resolution, calling for greater autonomy for what will become Pakistan in British India, is drawn up by the All-India Muslim League during a three-day general session at Iqbal Park, Lahore. March 30 – WWII: Former Kuomintang member and Chinese foreign minister, Wang Jingwei, announces the creation of the Reorganized National Government of the Republic of China in Nanjing. March 31 – WWII: Commerce raiding leaves the Wadden Sea for what will become the longest warship cruise of the war (622 days without in-port replenishment or repair).

April

April 3 – WWII: Operation Weserübung – German ships set out for the invasion of Norway. April 4 – Neville Chamberlain, UK Prime Minister, in what proves to be a tragic misjudgment, declares in a major public speech that Hitler has "missed the bus". April 7 – Booker T. Washington becomes the first African American to be depicted on a United States postage stamp. April 8 – WWII: Operation Wilfred: The British fleet lays naval mines off the coast of neutral Norway. April 9 – WWII: Germany invades the neutral countries of Denmark and Norway in Operation Weserübung, opening the Norwegian campaign. The British Royal Navy attempts to attack elements of the German fleet off Norway. Vidkun Quisling proclaims a new collaborationist regime in Norway. The German invasion of Denmark lasts for about six hours, before that country capitulates. April 10 – WWII: First naval Battle of Narvik – The British Royal Navy attacks the German fleet in the Ofotfjord. At Bergen, German cruiser Königsberg is sunk by British Fleet Air Arm Blackburn Skua dive bombers, flying from RNAS Hatston in Orkney. April 12 The Faroe Islands are occupied by British troops, following the German invasion of Denmark. This action is taken to avert a possible German occupation of the islands, with serious consequences for the course of the Battle of the Atlantic. Opening day at Jamaica Race Course features the use of parimutuel betting equipment, a departure from bookmaking heretofore used exclusively throughout New York. Other tracks in the state follow suit later in 1940. April 13 – WWII: Second naval Battle of Narvik – The British Royal Navy sinks all 8 defending German destroyers in the Ofotfjord. April 14 – WWII: Norwegian campaign – The first British ground forces land in Norway, at Namsos and Harstad. April 23 – The Rhythm Club fire at a dance hall in Natchez, Mississippi, United States, kills 198 people. April 27 – Mandatory Palestine and Lebanon play an association football friendly; it is Lebanon's first official match, and Mandatory Palestine's last before they become Israel in 1948.

May

May 10 – WWII: The Battle of France begins. German forces invade the Low Countries: The Battle of the Netherlands begins. The Battle of Belgium begins. The Invasion of Luxembourg begins. The British invasion of Iceland begins. With the resignation of Neville Chamberlain, Winston Churchill becomes Prime Minister of the United Kingdom. May 13 – WWII: Winston Churchill, in his first address as Prime Minister, tells the House of Commons of the United Kingdom, "I have nothing to offer you but blood, toil, tears and sweat." German armies open a wide breach in the Maginot Line at Sedan, France. May 13–14 – Queen Wilhelmina of the Netherlands and her government are evacuated to London, using the British destroyer . May 14 – WWII: Rotterdam is subjected to savage terror bombing by the Luftwaffe; 980 are killed, and 20,000 buildings destroyed. General Henri Winkelman announces the surrender of the Dutch army (outside Zeeland) to German forces. Recruitment begins in Britain for a volunteer home defence force: the Local Defence Volunteers, later known as the Home Guard. May 15 WWII: The Dutch Army formally signs a surrender document. Women's stockings made of nylon are first placed on sale across the United States. Almost five million pairs are bought on this day. May 16 – President of the United States Franklin D. Roosevelt, addressing a joint session of the U.S. Congress, asks for an extraordinary credit of approximately $900,000,000 to finance construction of at least 50,000 airplanes per year. May 17 – WWII: Brussels falls to German forces; the Belgian government flees to Ostend. Zeeland is overrun by German forces, ending the Battle of the Netherlands and beginning full German occupation of the Netherlands (Noord-Beveland surrenders on May 18, and the remaining Dutch troops are withdrawn from Zeelandic Flanders on May 19). May 18 – Marshal Philippe Pétain is named vice-premier of France. May 19 – General Maxime Weygand replaces Maurice Gamelin as commander-in-chief of all French forces. May 20 WWII: German forces (2nd Panzer Division), under General Rudolf Veiel, reach Noyelles on the English Channel. The Holocaust: The Nazi concentration camp and extermination camp Auschwitz-Birkenau, the largest of the German concentration camps, opens in occupied Poland, near the town of Oświęcim. From now on until January 1945, around 1.1 million people will be killed here. May 22 – WWII: The Parliament of the United Kingdom passes the Emergency Powers (Defence) Act 1940, giving the government full control over all persons and property. May 24 – WWII: The Anglo-French Supreme War Council decides to withdraw all forces under its control from Norway. Hitler issues Der Halte Befehl, a stop order preventing his Panzer divisions advancing on Dunkirk. May 25 – The Crypt of Civilization time capsule at Oglethorpe University, Brookhaven, Georgia in the United States, is sealed shut, with a projected opening date of 8113 CE. May 26 WWII: The Dunkirk evacuation of the British Expeditionary Force from France begins. The first free flight of Igor Sikorsky's Vought-Sikorsky VS-300 helicopter is made in the United States. May 27 – WWII: Le Paradis massacre: 97 retreating British soldiers of the Royal Norfolk Regiment are executed by German troops of 3rd SS Panzer Division Totenkopf after surrendering in France. May 28 – WWII: (04:00) Surrender of Belgian forces on the orders of King Leopold III, ending the 18-day Battle of Belgium. Leaders of the Belgian government in exile (on French territory at this time) declare Leopold's action to be unconstitutional; he is placed under house arrest by the German occupiers. Land battle of Narvik: German forces retire, giving the Allies their first victory on land in the war; however, the British have already decided to evacuate Narvik. Winston Churchill warns the House of Commons of the United Kingdom to "prepare itself for hard and heavy tidings." The Wormhoudt massacre (or Wormhout massacre) takes place with the mass murder of 80 British and French POWs by Waffen-SS soldiers from the 1st SS Division Leibstandarte SS Adolf Hitler during the Battle of France. May 29 – The Vought XF4U-1, prototype of the F4U Corsair U.S. fighter later used in WWII, makes its first flight.

June

June 1 – WWII: Rear Admiral Sir W. Frederic Wake-Walker's flagship, the destroyer Keith, is sunk by Stukas at Dunkirk. June 3 WWII: Paris is bombed by the Luftwaffe for the first time. The Holocaust: Franz Rademacher proposes the Madagascar Plan. The Weather Bureau is transferred to the United States Department of Commerce. June 4 – WWII: The Dunkirk evacuation ends: The British and French navies, together with large numbers of civilian vessels from various nations, complete evacuating 300,000 troops from Dunkirk, France to England. Winston Churchill tells the House of Commons of the United Kingdom, "We shall not flag or fail. We shall fight on the beaches... on the landing grounds... in the fields and the streets.... We shall never surrender." June 7 – King Haakon VII of Norway and his government are evacuated from Tromsø to London, on HMS Devonshire. June 10 – WWII: Italy declares war on France and the United Kingdom. U.S. President Franklin D. Roosevelt denounces Italy's actions with his "Stab in the Back" speech during the graduation ceremonies of the University of Virginia."Stab in the Back" Canada declares war on Italy. The Norwegian Army surrenders to German forces. The French government flees to Tours.