1: 10,000 Japanese troops launch a counter-attack in eastern Shanxi Province in China in an attempt to relieve the nearly-surrounded Japanese 36th Division.
2: The Soviet offensive in Finland is halted by several Finnish victories; numerous Soviet tanks are destroyed.
7: Rationing of basic foodstuffs is established in the UK. A major Finnish victory at Suomussalmi is reported; one whole Soviet division is eliminated, and again numbers of military vehicles are captured.
7: General Semyon Timoshenko takes command of Soviet Army forces in Finland.
16: Captured documents reveal Hitler's plans for the invasion of Scandinavia and a postponement of the invasion of France and the Low Countries until the spring, when the weather is more compatible for an invasion.
17: The Soviets are driven back in Finland and retaliate with heavy air attacks.
20: German submarine U-44 torpedoes and sinks Greek steamer Ekatontarchos Dracoulis off Portugal at 0415 hours, killing 6. U-44 had been hunting for Ekatontarchos Dracoulis for the past 6 hours.
21: A U-boat sinks British destroyer HMS Exmouth and its crew of 135 are all lost.
24: Reinhard Heydrich is appointed by Göring for the solution to the "Jewish Question".
27: Germany makes final plans for the invasion of Denmark and Norway.
Finnish ski troops in Northern Finland January 12, 1940.
1: The Japanese Diet announces a record high budget with over half its expenditures being military.
5: Britain and France decide to intervene in Norway to cut off the iron ore trade in anticipation of an expected German occupation and ostensibly to open a route to assist Finland. The operation is scheduled to start about March 20.
9: Erich von Manstein is placed in command of German XXXVIII (38) Armour Corps, removing him from planning the French invasion.
10: USSR agrees to supply grain and raw materials to Germany in a new trade treaty.
14: British government calls for volunteers to fight in Finland.
30: Britain undertakes secret reconnaissance flights to photograph the targeted areas inside the Soviet Union in preparation for Operation Pike, utilising high-altitude, high-speed stereoscopic photography pioneered by Sidney Cotton.
April: 22,000 Polish officers, policemen, and others are massacred by the Soviet NKVD in the Katyn massacre.
14: The creation of the Local Defence Volunteers (the Home Guard) is announced by the new Secretary of State for WarAnthony Eden. It is mostly composed of the elderly and retired. Churchill asks President Roosevelt and Canada for aid in these dark days. Outlines of the new British coalition, which includes Labour, Liberal, and Conservative members, is made public.
14: The Rotterdam Blitz led to German success in the Battle of Rotterdam, while causing many civilian deaths and tremendous damage. The Netherlands decided to surrender with the exception of Zealand.
15: The capitulation of the Dutch army is signed. In a response to the Rotterdam Blitz, the first large-scale strategic bombing of World War II targets Gelsenkirchen, followed by Hamburg, Bremen, Cologne, Essen, Duisburg, Düsseldorf and Hanover during the next days. German forces cross over the Meuse River.
16: Churchill visits Paris and hears that the French war is as good as over.
16: The Belgian government leaves Belgium for Bordeaux in France, as the Belgian army retreats. It later moves to London.
17: Germans enter Brussels and also take Antwerp. Paul Reynaud forms new French government, including 84-year-old Marshal Pétain, the French hero of World War I.
19: Amiens in France is besieged by German troops; Rommel's forces surround Arras; other German forces reach Noyelles on the Channel.
19: The British complete their invasion of Iceland.
20: General Guderian's Panzer groups take Abbeville, threatening Allied forces in the area.
23: Oswald Mosley, leader of the pre-war British fascists, is jailed; he and his wife will spend the duration in prison.
24: The British make a final decision to cease operations in Norway.
25: The Allied forces, British and French alike, retreat to Dunkirk. Hitler orders a halt to the advance of Germans toward the Allied beachhead and allows Hermann Göring to use the Luftwaffe to attack. British R.A.F. defends the beachhead. Sporadic Luftwaffe bombings in England. Boulogne-sur-Mer surrenders to the Germans.
25: Soviet Union is preparing a total takeover in the Baltic States organizing and staging conflicts between the Baltic States and the USSR. Soviet government accuses Lithuania of kidnapping Soviet soldiers.
13: French government moves again, this time to Bordeaux.
14: Paris occupied by German troops; Elements of the French Navy (Marine Nationale) based in Toulon carried out offensive operations against Italian targets along the Ligurian coast. A total military blockade on the Baltic States by the Soviet Baltic Fleet. Soviet troops along the Baltic borders are ready to organise communist coups in the Baltic States. Soviet bombers shoot down a Finnish passenger airplane Kaleva flying from Tallinn to Helsinki and carrying three diplomatic pouches from the U.S. legations in Tallinn, Riga and Helsinki.
15: Eight-hour ultimatum to surrender is given to Lithuania by the Soviets. President Smetona escapes from the country so the takeover is not possible to do in a formally legal way. Soviet troops enter Lithuania and attack Latvian border guards. Start of the evacuation of British troops from ports in western France in Operation Aerial.
16: Philippe Pétain becomes premier of France upon the resignation of Reynaud's government. The French sloop La Curieuse forces the Italian submarine Provano to surface and then sinks it by ramming. Soviet Union gives eight-hour ultimatum to Latvia and Estonia to surrender.
17: Sinking of liner RMS Lancastria off St Nazaire while being used as a British troopship— at least 3,000 are killed in Britain's worst maritime disaster. Soviet troops enter Latvia and Estonia.
21: The French battleship Lorraine opened fire on the Italian port of Bardia in Italian North Africa. During some of the last actions of the French against the Italians, French naval aircraft attacked Taranto and Livorno in mainland Italy.
21: Soviet-led coups in the Baltic States. In the only military resistance in Tallinn, 2 die on Estonian side and about 10 on the Soviet side.
25: France officially surrenders to Germany at 01:35. Last major evacuation of Operation Aerial; 191,870 Allied soldiers, airmen and some civilians had escaped from France.
26: The Soviet Union send an ultimatum demanding Bessarabia and Northern Bukovina from Romania.
27: Romanians propose negotiations. Molotov replies that the demands are land concessions or war. New ultimatum from the Soviets to the Romanians.
28: General De Gaulle recognised by British as leader of Free French. : Marshal Italo Balbo, Commander-in-Chief of Italian North Africa, is accidentally killed in a "friendly fire incident" by Italian anti-aircraft fire at Tobruk, Libya. : The Red Army occupies Romanian Bessarabia and the northern part of Bukovina. : The Luftwaffe bombs the demilitarised British Channel Islands, they had not been informed of the demilitarization. In Guernsey, 33 are killed and 67 injured, in Jersey, 9 are killed and many are injured. : Axis and Allied convoys clash south-west of Crete.
29: Japanese Foreign Minister Hachiro Arita announces Japans intention to establish a bloc of Asian nations led by the Japanese and free from western powers.
4: Sark surrenders to the Germans. The Germans now control all of the British Channel Islands.
4: The German News Bureau released excerpts of the documents captured during the fall of France relating to Operation Pike, an Anglo-French plan to bomb Soviet oil fields. The compromised operation was subsequently aborted.
22: The Havana Conference meets; the nations of the Western hemisphere meet to discuss neutrality and economic cooperation. Fumimaro Konoye is named the Prime Minister of Japan.
23: The British "Home Guard" is officially established, drawing on elderly men and those considered unable to serve in the regular armed forces.
25: All women and children are ordered to evacuate Gibraltar.
26: The United States of America activates the General Headquarters (GHQ), United States Army, which is designed to facilitate mobilization by supervising the organization and training of the army field forces within the continental United States, which is code named the Zone of the Interior.
August: The so-called Spéngelskrich ("War of Pin-badges") begins in occupied Luxembourg as civilians wear patriotic lapel badges prominently, in defiance of Nazi attempts to "Germanize" the territory.
1: Hitler sets 15 September as the date for Operation Sea Lion, the invasion of Britain. : Soviet Foreign Minister Molotov reaffirms Molotov-Ribbentrop pact in the Soviet Supreme while verbally attacking both Britain and the USA. He also asserts that the boundaries of the Soviet Union are moved to the shores of the Baltic Sea. : The Italian Royal Navy establishes its BETASOM submarine base in Bordeaux and joins the "Battle of the Atlantic."
1-4: Operation Hurry, the first of the Malta Convoys, is accomplished.
13: This is "Adler Tag" or "Eagle Day". Hermann Göring starts a two-week assault on British airfields in preparation for invasion. (For some German historians, this is the beginning of the "Battle of Britain.")
14: British scientist Sir Henry Tizard leaves for the United States on the Tizard Mission, giving over to the Americans a number of top secret British technologies including the magnetron, the secret device at the heart of radar. Radar is already proving itself in the defence of Britain.
15: RAF victories over the Luftwaffe continue, in a wide-ranging fight along the East coast. British fighter aircraft production begins to accelerate. : Sinking of the Greek cruiser Elli by an Italian submarine on 15 August 1940 at the harbour of Tinos.
17: Hitler declares a blockade of the British Isles.
18: Heavy fighting in the Battle of Britain; Germans suffering severe losses on bomber formations. Göring declares cowardice among his fighter pilots and orders them to closely guard the bombers, further restricting their capabilities.
19: Italian forces take Berbera, the capital of British Somaliland and the British defenders flee to Aden. The fall of Berbera completes the invasion of the British colony. By the end of the month, the Italians control British Somaliland and several towns and forts along the border with Sudan and Kenya including Kassala, Gallabat, and Moyale.
3: Hitler postpones the invasion of Britain, as the Luftwaffe fails to break the British defenses. However, fears of the forthcoming invasion continue to haunt Britain.
6: King Carol abdicates the Romanian throne in favour of his son Michael while control of the government is taken by Marshal Antonescu.
7: In one of the major misjudgements of the war, the Luftwaffe shifts its focus to London, away from the RAF airfields. Success may be measured only in the estimated 2,000 civilian dead. Other British cities are hit. The Blitz starts.
13: After re-taking Fort Capuzzo just inside Libya, Italian colonial forces cross the border and advance into Egypt. The Italians take the small port of Sollum, but the only resistance to the invasion is a light British screening force which withdraws as the Italians advance.
14: Operation Sea Lion is postponed until 27 September, the last day of the month with suitable tides for the invasion.
15: Massive German bombing flights on English cities; most are driven off. The RAF begins to claim victory in the Battle of Britain.
28: At about 03:00 am the Italian ambassador to Greece issues ultimatum to Greece and Greek Prime Minister Metaxas replies: "So it is war". The Italian Royal Army launches attacks into Greece from Italian-held Albania. Hitler is angered at the initiative of his ally.
29: Very heavy convoy losses during this period as numbers of U-boats increase.
11: British naval forces launch attack against Italian navy at Taranto. Swordfish bombers from HMS Illustrious damage three battleships, two cruisers and multiple auxiliary craft. The event secures British supply lines in the Mediterranean. The British success will be studied by Japanese military already preparing for an attack on Pearl Harbor.
12: Molotov meets Hitler and Ribbentrop in Berlin. New World order is under discussion. Molotov expresses Soviet interest in Finland, Bulgaria, Romania, Dardanelles and Bosporus, but Hitler talks along broad lines about worldwide spheres of influence between Russia, Germany, Italy and Japan.
12: In the Battle of Gabon, British forces finish wresting central Africa from the Vichy French.
13: Molotov meets Hitler again asking acceptance to liquidate Finland. Hitler now resists every attempt to expand Soviet influence in Europe. He sees Britain as defeated and offers India to the Soviet Union. : The Battle of Pindus ends in a Greek victory.
15: The Soviet Union is invited to join Tripartite Pact and to share in the spoils of British Empire. Warsaw's Jewish ghetto is cordoned off from the rest of the city.
16: Churchill orders some British troops in North Africa to be sent to Greece, despite concerns by his military leaders that they are needed in the current campaign against the Italians in North Africa.
19: The Greeks continue to advance, and evict Italian troops from Greek soil.
1: Bombing raids are exchanged throughout the month between Germany and Britain. First Germany bombs, then Britain.
Joseph P. Kennedy, the US Ambassador to the United Kingdom is asked to resign by President Roosevelt after he gives a newspaper interview expressing the view that "Democracy is finished in England".
5: The RAF bombs Düsseldorf and Turin.
6-9: British and Indian troops of the Western Desert Force launch Operation Compass, an offensive against Italian forces in Egypt. The Italians have seven infantry divisions and the Maletti Group in fortified defensive positions. Initial attacks are launched against the five Italian camps around and south of Sidi Barrani. The camps are overrun, Italian General Pietro Maletti is killed, and the Maletti Group, the 1st Libyan Division, the 2nd Libyan Division, and the 4th Blackshirt Division are all but destroyed. The remaining Italian units in Egypt are forced to withdraw towards Libya.
8: Francisco Franco rules out Spanish entry into the war; the immediate result is that Hitler is forced to cancel an attack on Gibraltar.
12: In North Africa, over 39,000 Italians lost or captured in Egypt.
16: The first RAF night raid--on Mannheim, Germany. : In North Africa, the British are in command at Sollum in Egypt and take Fort Capuzzo in Libya.
18: Hitler issues directive to begin planning for Operation Barbarossa, the German invasion of the Soviet Union.