Timeline of World War II
Twenty-two dates that carry the shape of the war in Europe and the Pacific. Each line names the institution whose records it can be checked against; the wording is ours.
Updated on October 7, 2026
1939 to 1945
September 1, 1939
Germany invades Poland; the Second World War begins in Europe.
Source: Imperial War Museums — cronologias da Segunda Guerra Mundial
September 3, 1939
The United Kingdom and France declare war on Germany.
Source: Imperial War Museums — cronologias da Segunda Guerra Mundial
April 9, 1940
German forces occupy Denmark and invade Norway.
Source: Imperial War Museums — cronologias da Segunda Guerra Mundial
May 10, 1940
Germany attacks the Netherlands, Belgium, Luxembourg and France. Winston Churchill becomes prime minister.
Source: Imperial War Museums — cronologias da Segunda Guerra Mundial
June 4, 1940
The Dunkirk evacuation ends: about 338,000 Allied soldiers are taken off the French coast.
Source: Imperial War Museums — cronologias da Segunda Guerra Mundial
June 22, 1940
France signs an armistice with Germany; the country is split into an occupied zone and the Vichy state.
Source: Imperial War Museums — cronologias da Segunda Guerra Mundial
July 10, 1940
The Battle of Britain opens; the RAF holds off the Luftwaffe until the end of October.
Source: Imperial War Museums — cronologias da Segunda Guerra Mundial
June 22, 1941
Operation Barbarossa: Germany invades the Soviet Union along a front of some 2,900 km.
Source: U.S. National Archives — World War II e Cold War records
December 7, 1941
Japan attacks Pearl Harbor. The United States declares war on Japan the next day.
Source: U.S. National Archives — World War II e Cold War records
December 11, 1941
Germany and Italy declare war on the United States.
Source: U.S. National Archives — World War II e Cold War records
January 20, 1942
The Wannsee Conference coordinates the machinery of the "final solution", the planned murder of Europe’s Jews.
Source: United States Holocaust Memorial Museum — Holocaust Encyclopedia
June 4, 1942
Battle of Midway: the United States sinks four Japanese carriers and turns the Pacific war.
Source: U.S. National Archives — World War II e Cold War records
February 2, 1943
The German 6th Army surrenders at Stalingrad after five months of siege.
Source: U.S. National Archives — World War II e Cold War records
July 10, 1943
Operation Husky: the Allies land in Sicily, the first large landing in Europe.
Source: Imperial War Museums — cronologias da Segunda Guerra Mundial
September 8, 1943
Italy's armistice with the Allies is announced; German troops occupy the centre and north of the country.
Source: Imperial War Museums — cronologias da Segunda Guerra Mundial
June 6, 1944
D-Day: the Allies land in Normandy with about 156,000 men on the first day.
Source: U.S. National Archives — World War II e Cold War records
August 25, 1944
Paris is liberated.
Source: U.S. National Archives — World War II e Cold War records
January 27, 1945
Soviet troops reach Auschwitz-Birkenau and free the prisoners still in the camp.
Source: United States Holocaust Memorial Museum — Holocaust Encyclopedia
April 30, 1945
Adolf Hitler kills himself in Berlin as Soviet troops close in on the city centre.
Source: U.S. National Archives — World War II e Cold War records
May 8, 1945
Germany’s unconditional surrender takes effect: Victory in Europe Day.
Source: U.S. National Archives — World War II e Cold War records
August 6, 1945
The United States drops an atomic bomb on Hiroshima; a second falls on Nagasaki on 9 August.
Source: U.S. National Archives — World War II e Cold War records
September 2, 1945
Japan signs the instrument of surrender aboard the USS Missouri; the war ends.
Source: U.S. National Archives — World War II e Cold War records
Source: U.S. National Archives — World War II e Cold War records
What a timeline like this leaves out
A list of dates is a skeleton. It makes the war look like a sequence of decisions, when most of it was six years of occupation, bombing, hunger and industrial killing that has no single date. The Holocaust appears here as two lines — Wannsee and the liberation of Auschwitz — for about six million murdered Jews and millions of other victims, which is the clearest example of how much a timeline compresses.
The start date is also a choice. 1 September 1939 is the standard European answer, but Japan invaded China in 1937, Italy took Ethiopia in 1935, and from a Chinese or Ethiopian point of view the war was already running. Total deaths are usually put between 70 and 85 million, the majority of them civilians, and the Soviet Union and China account for the largest shares.
Source: Imperial War Museums — cronologias da Segunda Guerra Mundial
How to read this page
How to read the numbers here
Every value on "Timeline of World War II" comes from the source named beside its section, never from an estimate of our own with no origin.
Where the data comes from
Each section of "Timeline of World War II" names its official source; the verification date sits at the top of the page.
Linked to the rest of the module
"Timeline of World War II" is one of this module’s reference pages; the glossary below defines the technical terms used here.
More about “Timeline of World War II”
6 years in 22 dates
"Timeline of World War II" spans 6 years, from 1939 to 1945, in 22 chosen dates — averaging one marked event every 0.3 years. That spacing is our editorial choice, not a law of history: tenser periods had more events that could have made the list than quieter ones.
Words on this page
Standard uncertainty
The margin attached to a measured value, usually written in parentheses on the last digits. A constant that is "exact by definition" has zero standard uncertainty; a measured one, like the gravitational constant G, always carries some.
Standard definition by BIPM — Bureau International des Poids et Mesures (SI) · Standard uncertainty
Launch window
The span of time in which a rocket can lift off and still reach its planned orbit or destination. For a trip to another planet that window can last only a few weeks and only returns at the next favourable alignment, so missing it costs months or years of waiting.
Astronomical unit
The solar system’s reference distance, fixed at exactly 149,597,870,700 metres since 2012, close to the average Earth–Sun distance. It saves writing every planet’s orbit in kilometres with ten digits.
Standard definition by IAU — International Astronomical Union · Astronomical unit
Exoplanet
A planet orbiting a star other than the Sun. Most were found indirectly, by the star’s faint dimming as the planet crosses in front of it (transit) or by the gravitational wobble it causes in the star (radial velocity), not by direct image.
Standard definition by NASA Exoplanet Archive · Exoplanet
Mole
The SI counting unit for atoms, molecules or other entities: one mole is exactly 6.02214076 × 10²³ of them, by the definition fixed in 2019. It is what ties a mass in grams to a number of particles.
Standard definition by BIPM — Bureau International des Poids et Mesures (SI) · Mole