Below, events of World War II have the WWII prefix.
Further Information: January 1939
- January 3 – EFE, a news agency, based in Madrid, Spain, is officially founded as a limited company.
- January 5 – Amelia Earhart is officially declared dead after her disappearance.
- January 6 – Naturwissenschaften publishes evidence that nuclear fission has been achieved by Otto Hahn.
- January 13 – Black Friday: 71 people die across Victoria in one of Australia's worst ever bushfires.
- January 14 – Norway claims Queen Maud Land in Antarctica.
- January 23 – "Dutch War Scare": Admiral Wilhelm Canaris of the Abwehr leaks misinformation to the effect that Germany plans to invade the Netherlands in February, with the aim of using Dutch air-fields to launch a strategic bombing offensive against Britain. The "Dutch War Scare" leads to a major change in British policies towards Europe.
- January 24 – 1939 Chillán earthquake: An earthquake in Chile kills 30,000 and razes about 50,000 sq mi (130,000 km2).
- January 25 – Refik Saydam forms the new (11th) government of Turkey.
- January 26
- Spanish Civil War: Spanish Nationalist troops, aided by Italy, take Barcelona.
- In Paris, French Foreign Minister Georges Bonnet, in response to rumours (which are true) that he is seeking to end the French alliance system in Eastern Europe, gives a speech highlighting his government's commitment to the cordon sanitaire.
- January 27 – Adolf Hitler orders Plan Z, a 5-year naval expansion programme intended to provide for a huge German fleet capable of crushing the Royal Navy by 1944. The Kriegsmarine is given the first priority on the allotment of German economic resources.
- January 30 – Hitler gives a speech before the Reichstag calling for an "export battle" to increase German foreign exchange holdings. The same speech also sees Hitler's "prophecy" where he warns that if "Jewish financers" start a war against Germany, the...result will be the annihilation of the Jewish race in Europe".
Further Information: February 1939
Further Information: March 1939
- March – The 1936–39 Arab revolt in Palestine ends.
- March 1 – An Imperial Japanese Army ammunition dump explosion on the outskirts of Osaka kills 94.
- March 2 – Pope Pius XII (Cardinal Pacelli) succeeds Pope Pius XI as the 260th pope.
- March 3
- In Bombay, Mahatma Gandhi begins a fast protesting against British rule in India.
- Students at Harvard University demonstrate the new tradition of swallowing goldfish to reporters.
- In Durban, South Africa the Timeless Test begins between England and South Africa, the longest game of cricket ever played. It is abandoned twelve days later when the English team has to catch the last ferry home.
- March 13
- March 14 – The Slovak provincial assembly proclaims independence; priest Jozef Tiso becomes the president of the independent Slovak government.
- March 15 – German troops occupy the remaining part of Bohemia and Moravia; Czechoslovakia ceases to exist. The Ruthenian region of Czechoslovakia declares independence as Carpatho-Ukraine.
- March 16
- March 17
- British Prime Minister Neville Chamberlain gives a speech in Birmingham, stating that Britain will oppose any effort at world domination on the part of Germany.
- The nationalist governments of Spain and Portugal sign the Iberian Pact in Lisbon, pledging mutual defence of the Iberian Peninsula and neutrality in the event of a general European war.
- March 18 – "Romanian War Scare": Virgil Tilea, the Romanian Minister in London, spreads false rumours that Romania is on the verge of a German attack.
- March 19 – Hitler sends a registered letter to the government of Lithuania stating that Germany intends to annex the port of Memel.
- March 20 – At an emergency meeting in London to deal with the Romanian crisis, French Foreign Minister Georges Bonnet suggests to Lord Halifax that the ideal state for saving Romania from a German attack is Poland.
- March 21 – In London: the Ordo Templi Orientis publish Aleister Crowley's Eight Lectures on Yoga.
- March 22
- March 23 – The Slovak–Hungarian War begins.
- March 24 – Marks the seventh successive year of the worldwide boycott of all German exports initiated by front page declarations in Britain and the U.S. 'Judea declares war on Germany'
- March 27 – The University of Oregon defeats Ohio State University 46–33 in Evanston, Illinois, to win the championship of the first NCAA men's basketball tournament.
- March 28
- Dictator Francisco Franco assumes power in Madrid, remaining in power until his death in 1975.
- American adventurer Richard Halliburton delivers a last message from a Chinese junk, before he disappears on a voyage across the Pacific Ocean. In 1945, some wreckage identified as a rudder and believed to belong to the junk, washed ashore in San Diego, California.
- March 31 – Neville Chamberlain gives a speech in the House of Commons offering the British "guarantee" of the independence of Poland.
Further Information: April 1939
- April 1
- The Spanish Civil War comes to an end when the last of the Republican forces surrender.
- The rumor that Hitler is dead sweeps the United States as millions of CBS radio listeners hear the Führer cut off in mid-speech during a shortwave relay of his address at the dedication of the Tirpitz in Wilhelmshaven.
- April 3
- Adolf Hitler orders the German military to start planning for Fall Weiß, the codename for the invasion of Poland.
- Refik Saydam forms the new government in Turkey (12th government; Refik Saydam had served twice as a prime minister).
- April 4
- Faisal II becomes King of Iraq at age 3 following the death of his father, Ghazi, in an automobile incident.
- The Slovak–Hungarian War ends with Slovakia ceding eastern territories to Hungary.
- Polish Foreign Minister Colonel Józef Beck, in London, signs a treaty designed to bilateralize Neville Chamberlain's "Polish Guarantee" of March 31.
- April 7
- April 9 – African-American singer Marian Anderson performs before 75,000 people at the Lincoln Memorial in Washington, D.C., after having been denied the use both of Constitution Hall by the Daughters of the American Revolution, and of a public high school by the federally controlled District of Columbia. First Lady of the United States Eleanor Roosevelt resigns from the DAR because of their decision.
- April 11 – Hungary leaves the League of Nations.
- April 13 – Britain offers a "guarantee" to Romania and Greece.
- April 14
- John Steinbeck's novel The Grapes of Wrath is first published, in the United States.
- At a meeting in Paris, French Foreign Minister Georges Bonnet meets with Soviet Ambassador Jakob Suritz, and suggests that a "peace front" comprising France, the Soviet Union, Great Britain, Poland and Romania would deter Germany from war.
- April 18
- April 20 – Billie Holiday records "Strange Fruit", the first anti-lynching song.
- April 25 – The Federal Security Agency (FSA) is founded in the United States, along with the Civilian Conservation Corps and Public Health Service.
- April 27 – Ely Racecourse in Cardiff closes.
- April 28 – In a speech before the Reichstag, Adolf Hitler renounces the Anglo-German Naval Agreement and the German–Polish Non-Aggression Pact.
- April 30 – The 1939 New York World's Fair opens.
Further Information: May 1939
- May 1 – Batman, created by Bill Finger and Bob Kane, makes his first appearance in Detective Comics #27.
- May 2 – Major League Baseball's Lou Gehrig, the legendary Yankee first baseman known as "The Iron Horse", ends his 2,130 consecutive games-played streak, after being diagnosed with amyotrophic lateral sclerosis. The record stands for 56 years before Cal Ripken, Jr. plays 2,131 consecutive games.
- May 3
- May 6 – Carl Friedrich Goerdeler tells the British government that the German and Soviet governments are secretly beginning a rapprochement with the aim of dividing Eastern Europe between them. Goerdeler also informs the British of German economic problems which he states threaten the survival of the Nazi regime, and advises that if a firm stand is made for Poland, then Hitler will be deterred from war.
- May 9 – Spain leaves the League of Nations.
- May 14 – Lina Medina, a 5-year-old Peruvian girl, gives birth to a baby boy, becoming the youngest confirmed mother in medical history.
- May 17
- May 18 – The Hòa Hảo religious sect is established by Huỳnh Phú Sổ.
- May 20 – Pan American Airways begins transatlantic mail service with the inaugural flight of its Boeing 314 flying boat Yankee Clipper from Port Washington, New York, to Marseille.
- May 22 – Germany and Italy sign the Pact of Steel.
- May 24 – First issue of Fashizmi is published in Tirana.
- May 29 – Albanian fascist leader Tefik Mborja is appointed as member of the Italian Chamber of Fasces and Corporations.
Further Information: June 1939
- June 3 – The Soviet government offers its definition of what constitutes "aggression", upon which the projected Anglo-Soviet-French alliance will come into effect. The French Foreign Minister Georges Bonnet accepts the Soviet definition of aggression at once. The British reject the Soviet definition, especially the concept of "indirect aggression", which they feel is too loose a definition and phrased in such a manner as to imply the Soviet right of inference in the internal affairs of nations of Eastern Europe.
- June 4 – The St. Louis, a ship carrying a cargo of 907 Jewish refugees, is denied permission to land in Florida after already having been turned away from Cuba. Forced to return to Europe, many of its passengers later die in Nazi death camps during The Holocaust.
- June 6 – The first Little League Baseball game is played in Williamsport, Pennsylvania.
- June 10 – MGM's first successful animated character, Barney Bear, makes his debut in The Bear That Couldn't Sleep. However, he didn't have a name until 1942.
- June 12 – The National Baseball Hall of Fame and Museum is officially dedicated in Cooperstown, New York.
- June 14 – Tientsin Incident: The Japanese blockade the British concession in Tianjin, China, beginning a crisis which almost causes an Anglo-Japanese war in the summer of 1939.
- June 17 – In the last public guillotining in France, murderer Eugen Weidmann is executed.
- June 21 – New York Yankees announce Lou Gehrig's retirement after doctors reveal he has amyotrophic lateral sclerosis.
- June 23 – Talks are completed in Ankara between French Ambassador René Massigli and Turkish Foreign Minister Şükrü Saracoğlu, resolving the Hatay dispute in Turkey's favor. Turkey annexes Hatay.
- June 24 – The government of Siam changes its name to Thailand, which means 'Free Land'.
- June 29 – Ford 9N tractor with Ferguson hydraulic three-point hitch first demonstrated at Dearborn, Michigan.
Further Information: July 1939
Further Information: August 1939
- August 2 – The Einstein–Szilárd letter is signed, advising President of the United States Franklin D. Roosevelt of the potential use of uranium to construct an atomic bomb.
- August 4 – Neville Chamberlain dismisses Parliament until October 3.
- August 15 – MGM's classic musical film The Wizard of Oz, based on L. Frank Baum's famous novel, and starring Judy Garland as Dorothy, premieres at Grauman's Chinese Theatre in Hollywood.
- August 19 – Adolf Hitler, after evaluating the pace of the non-aggression negotiations with the Soviet Union, orders the Kriegsmarine to begin the opening operations for Fall Weiss, the invasion of Poland. The German pocket battleship Admiral Graf Spee, along with the German pocket battleship Deutschland, as well as dozens of u-boats, cast off for their advance positions. According to William L. Shirer, Hitler spends the next few days worrying that the Russians will not come to terms in time for the rest of the invasion plans to unfold as scheduled.
- August 20 – Armored forces under the command of Soviet General Georgy Zhukov deliver a decisive defeat to Imperial Japanese Army forces in the Japanese-Soviet border war in Inner Mongolia.
- August 23 – Molotov–Ribbentrop Pact signed between Germany and the Soviet Union, a neutrality treaty that also agreed to division of spheres of influence (Finland, Estonia, Latvia, eastern Poland and Bessarabia (today Moldova), north-east province of Romania to the Soviet Union; Lithuania and western Poland to Germany). Its annex reassigns Lithuania to the Soviet Union.
- August 24 – As details of the Molotov–Ribbentrop Pact become public, Neville Chamberlain recalls the Parliament of the United Kingdom several weeks early. In a burst of legislation, a War Powers Act is approved; and HMG order the Royal Navy to be put on a war footing, all leaves to be cancelled, and the Naval and coast defense reserves to be called up, especially radar and anti-aircraft units. In addition, the last British and French private citizens in Germany are ordered home by their respective Governments.
- August 25
- The German Foreign Ministry cuts off all telegraph and telephone communication with the outside world in accordance with the plan for Fall Weiss. At approximately 1830 Central European time, Adolf Hitler postpones Fall Weiss for 5 days, after receiving a message from Benito Mussolini that he will not honor the Pact of Steel if Germany attacks Poland, and because Chamberlain's government has not fallen as a result of the German-Soviet Non-Aggression Pact. Some units already in their forward positions (the attack is scheduled for 0430 the next day) do not get the word in time and attack various targets along the border. That same day, Neville Chamberlain gives Edward Rydz-Śmigły his "ironclad guarantee" of assistance if Poland is attacked by Germany.
- An Irish Republican Army bomb explodes in the centre of Coventry, England, killing 5 people.
- MGM's classic musical film The Wizard of Oz, based on L. Frank Baum's famous novel, and starring Judy Garland as Dorothy, is released in theaters everywhere.
- August 26
- August 27 – A Heinkel He 178, the first turbojet-powered aircraft, flies for the first time with Captain Erich Warsitz in command.
- August 28 – The SS Normandie heads into New York Harbor where she will be interned on 3 September and cut up for scrap beginning in 1946.
- August 30 – Poland begins a mobilization against Nazi Germany.
- August 31 – Operation Himmler: Nazi German troops posing as Poles stage a series of false flag operations on the border (including the Gleiwitz incident) giving a pretext for the invasion of Poland.
Further Information: September 1939
Common parade of Wehrmacht and Red Army in Brest at the end of the Invasion of Poland. At the center Major General Heinz Guderian
and Brigadier Semyon Krivoshein
- September 1 – Beginning of WWII:
- Opening shots of World War II and Invasion of Poland: At 4:45am Central European Time, under cover of darkness, the German WW1-era battleship Schleswig-Holstein quietly slips her moorings at her wharf in Danzig harbor, drifts into the center of the channel, and commences firing on the fortress Westerplatte, a Polish army installation at the northeastern mouth of the port of the internationalized Free City of Danzig. Five minutes previously the bombing of Wieluń in the western part of Poland had begun. Shock-troops of the German Wehrmacht begin crossing the border into Poland. Bombing of Wieluń (two air-raids) follows.
- The Reichstag passes a statement stating that Adolf Hitler's second-in-command Reichsmarschall Hermann Göring should be appointed as Hitler's successor as Führer should Hitler die during the War. Rudolf Hess is to be appointed in Göring's place should anything befall Göring.
- Norway, Finland, Sweden and Switzerland declare their neutrality.
- September 1 - General George C. Marshall becomes Chief of Staff of the United States Army.
- September 2 – WWII:
- Following the invasion of Poland, the Free City of Danzig (modern-day Gdańsk, Poland) is annexed to Nazi Germany.
- Spain and the Irish Free State declare their neutrality.
- September 3 – WWII:
- September 4 – WWII:
- September 5 – WWII: The United States declares its neutrality in the war.
- September 6 – WWII: South Africa declares war on Germany.
- September 8
- Little Sisters of Jesus founded in Algeria by Little Sister Magdeleine.
- WWII: Forward elements of General Hoeppner's XVI Panzerkorps take up positions outside Warsaw. The world is stunned by the rapidity of the German advance and the Polish High Command is effectively isolated, but lack of infantry support and effective civilian resistance cause Hoeppner to halt outside the city itself.
- WWII: Polish troops on the Westerplatte are forced, due to lack of food and ammunition, to surrender. The garrison of about two hundred had held out against thousands of German forces (many of them naval officer cadets from Schleswig-Holstein) for seven days.
- September 9 – WWII: Troops of the Polish Poznań Army under the command of General Kutrzeba open the Battle of the Bzura, the largest and best organized counter-attack mounted by the Polish forces in the campaign of 1939. For the first few days all goes well and the Germans are forced to retreat; but quick reaction by mechanized units and the Luftwaffe soon take their toll and the operation bogs down.
- September 10 – WWII: Canada declares war on Germany, the only declaration of war by Canada.
- September 15 – WWII: Diverse elements of the German Wehrmacht surround Warsaw and demand its surrender. The Poles refuse and the siege begins in earnest.
- September 16 – A ceasefire ends the undeclared Border War between the Soviet Union (and Mongolian allies) and Japan.
- September 17 – WWII:
- September 18 – WWII: Orzeł incident: The Polish submarine ORP Orzeł escapes internment from Tallinn harbour, Estonia, leading both the Soviet Union and Germany to question Estonia's neutrality.
- September 19 – WWII: The Poznan pocket collapses, and the Germans capture, according to many sources, over 150,000 men. Many elements of General Tadeusz Kutrzeba's forces work their way into Warsaw under extreme difficulty.
- September 21
- Reinhard Heydrich, chief of the Security Police, sends a directive, the Schnellbrief, explaining that Jews living in towns and villages in the Polish occupation zones are to be transferred to ghettos, and Jewish councils, Judenräte, will be established to carry out the German authorities’ orders.
- Radio station WJSV in Washington, D.C. records an entire broadcast day for preservation in the National Archives.
- September 22 – WWII: Joint victory parade of Wehrmacht and Red Army in Brest-Litovsk at the end of the Invasion of Poland.
- September 24 – WWII: The Soviet Union issues an ultimatum to Estonia to allow Soviet military bases on its territory, which Estonia accepts on September 28. Similar ultimatums are issued to Latvia on October 5 and to Lithuania on October 10, who are forced to accept them as well.
- September 28 – WWII:
- September 29 – Gerald J. Cox, speaking at an American Water Works Association meeting, becomes the first person to publicly propose the fluoridation of public water supplies in the United States.
- September 30 – General Władysław Sikorski becomes Prime Minister of the Polish government-in-exile.
Further Information: October 1939
Further Information: November 1939
- November 1–2 – WWII: Physicist Hans Ferdinand Mayer writes the Oslo Report on German weapons systems and passes it to the British Secret Intelligence Service.
- November 4 – WWII: U.S. President Franklin D. Roosevelt orders the United States Customs Service to implement the Neutrality Act of 1939, allowing cash-and-carry purchases of weapons to non-belligerent nations.
- November 4 – Stewart Menzies is appointed head of the British Secret Intelligence Service.
- November 6
- November 8
- November 9 – WWII: Venlo Incident: Two British agents of SIS are captured by the Germans.
- November 15 – In Washington, D.C., U.S. President Franklin D. Roosevelt lays the cornerstone of the Jefferson Memorial.
- November 16 – Al Capone is released from Alcatraz, due to deteriorating health caused by syphilis.
- November 17 – WWII: To punish protests against the Nazi occupation of the Czech homeland, the Nazis storm the University of Prague and murder nine Czech graduate students, send over 1,200 to concentration camps, and close all Czech universities, an event which will be commemorated as International Students' Day.
- November 23 – WWII: British armed merchantman HMS Rawalpindi is sunk in the GIUK gap in an action against the German battleships Scharnhorst and Gneisenau.
- November 26 – Shelling of Mainila: The Soviet Union's Red Army shells the Russian village of Mainila, then claims that the fire originated from Finland, giving a casus belli for the Winter War.
- November 30 – WWII:
Further Information: December 1939
- December 2 – LaGuardia Airport opens for business in New York City.
- December 4 – WWII:
- December 9
- WWII: First soldier of the British Expeditionary Force killed: Corporal Thomas Priday triggers a French land mine.
- Hugh Harman's animated short Christmas film Peace on Earth is released by MGM in the United States.
- December 12 – WWII: HMS Duchess sinks after a collision with HMS Barham off the coast of Scotland with the loss of 124 men.
- December 13 – WWII – Battle of the River Plate: The German heavy cruiser Admiral Graf Spee is trapped by cruisers HMS Ajax, HMNZS Achilles, and HMS Exeter after a running battle off the coast of Uruguay. Graf Spee is scuttled by its crew off Montevideo harbor on December 17.
- December 14 – WWII – Winter War: The League of Nations expels the USSR for attacking Finland.
- December 15 – The epic historical romance film Gone with the Wind, starring Vivien Leigh, Clark Gable, Olivia de Havilland and Leslie Howard, premieres at Loew's Grand Theatre in Atlanta. Based on Margaret Mitchell's best-selling novel of 1936, it is the longest American film made up to this date (at nearly four hours) and rapidly becomes the highest-grossing film up to this time.
- December 18 – WWII – Battle of the Heligoland Bight: RAF Bomber Command, on a daylight mission to attack Kriegsmarine ships in the Heligoland Bight, is repulsed by Luftwaffe fighter aircraft.
- December 22 – The second cel-animated feature film and the first produced by an American studio other than Walt Disney Productions, Gulliver's Travels by Fleischer Studios and very loosely based upon the book by Jonathan Swift, is released.
- December 26 – Miners strike in Borinage, Belgium.
- December 27 – The 7.8 Mw Erzincan earthquake shakes eastern Turkey with a maximum Mercalli intensity of XII (Extreme), causing $20 million in damage, and leaving 32,700–32,968 dead.
- Kirlian photography is invented by Semyon Kirlian.
- A logging crew sets off a second forest fire in the Tillamook Burn of Oregon, which destroys 190,000 acres (770 km2).
- Sandia View Academy, a private Adventist school, is founded in Corrales, New Mexico,
- General Motors introduces the Hydra-Matic drive, the first mass-produced, fully automatic transmission, as an option in 1940 model year Oldsmobile automobiles.
- Enzo Ferrari founds Auto Avio Construzioni, the company that became Ferrari in 1947.