April 4th, 1942 (SATURDAY)
UNITED KINGDOM: US naval TF 39 arrives in Scapa Flow. CV Wasp and BB Washington are part of this TF. They are supplementing the British Home Squadron while Operation Ironclad against Madagascar is run.
FRANCE: During the day, RAF Bomber Command dispatches 12 Bostons and four Wellingtons, escorted by RAF Fighter Command fighters, to attack the St. Omer railroad yards; 12 aircraft attack but their bombs fall in fields near the town.
GERMANY: Hitler orders raids on British historic towns as revenge for the bombing of Lübeck: they are called Baedeker raids after the German tourist guidebooks.
Göbbels writes in his diary of his relief that the tough and resilient north Germans have been bombed rather than the softer southerners.
JAPAN: After a heated debate, Admiral NAGANO Osami, Chief of the Navy General Staff, agrees to a simultaneous Aleutian-Midway operation.
MALDIVE ISLANDS: The crew of an RCAF Catalina Mk. I of No. 413 (General Reconnaissance) Squadron based at Koggala, Ceylon, on a reconnaissance flight reports sighting a Japanese fleet in the Indian Ocean about 360 miles (579 kilometres) southeast of Ceylon. Vice Admiral Sir James Somerville, Commander of the British Eastern Fleet, sails from Addu Atoll in the Maldive Islands, located about 400 miles (644 kilometres) southwest of Ceylon, with the faster ships (Force "A") to attack and orders the heavy cruisers HMS Cornwall and Dorsetshire to join him southwest of Ceylon. The two cruisers are at Colombo, Ceylon.
Colombo: The Royal Navy's 200 years of supremacy in the Indian Ocean have ended. Its shoestring fleet of five battleships - all but one of them pre-1918 - and the distinctly middle aged carrier HMS HERMES has been scattered by the threat of Nagumo's fleet of five carriers and four battleships - all veterans of Pearl Harbor. The Japanese fleet cruises the defenceless eastern coasts of Ceylon and India. The British fleet is 600 miles away, and is no match for Nagumo's ships and First Air Fleet.
Today the British heavy cruisers HMS Cornwall and HMS Dorsetshire sail from Colombo at 2200 hours to rejoin the British Eastern Fleet.
COMMONWEALTH OF THE PHILIPPINES: In the II Corps area on Bataan, the Japanese attack is again preceded by a demoralizing artillery bombardment in conjunction with air attacks. The main line of resistance of Sector D collapses as the 41st Division, Philippine Army (PA), withdraws again and the 21st Division, PA, is forced from their main line of resistance to the reserve line in front of Mt Samat. After nightfall, the Japanese regroup for an assault on Mt Samat. Sector C has to refuse its left flank because of enemy breakthrough.
The Luzon Force sends two regiments of the Philippine Division, the U.S. 31st Infantry and the 45th Infantry, Philippine Scouts, to support the II Corps.
AUSTRALIA: The RAAF forms No. 18 (Netherlands East Indies) Squadron at Canberra, and equips it with 5 B-25s.
P-40E pilots of the USAAF 9th Pursuit Squadron (Interceptor) based at Darwin, Northern Territory, shoot down seven Mitsubishi G3M2, Navy Type 96 Attack Bombers (later assigned the Allied Code Name "Nell") and two Mitsubishi A6M2, Navy Type 0 Carrier Fighters ("Zeke") over Darwin between 1330 and 1405 hours.
U.S.A.: The Allies concur in the establishment and divisions of the Southwest Pacific Area and the Pacific Ocean Area proposed on 30 March.
The U.S. grants recognition to Free French administration in Equatorial Africa and appoints a Consul General to Brazzaville. Americans are granted permission to use the airfield at Point Noire, Congo in exchange for eight Lockheed Hudson bombers.
ATLANTIC OCEAN: Two unarmed US tankers are sunk by German U-boats: one is lost 225 miles (362 km) north of Puerto Rico by German submarine U-154 and the second 8 miles (13 km) off North Carolina by U-552. The ship's cargo of 91,500 barrels of crude oil catches fire.