Yom Hashoah, Israel’s Day of Remembrance of the Holocaust and Heroism, is held on the 27th day of Nissan (towards the end of April or beginning of May), one week after Pesach (Passover). The day is dedicated to the memory of the six million Jews killed by the Nazis and to the heroism of the Jewish resistance to the Holocaust. The date was set to mark the anniversary of the Warsaw Ghetto uprising on the eve of Pesach, April 19, 1943.
The memorial day was first marked in 1951, and was decreed by law in 1959. The law stipulates that all places of entertainment including restaurants and cafes are closed from the eve of Yom Hashoah till the following evening. Memorial services are held throughout the country, and the central state ceremony takes place at Yad Vashem, Israel’s official Holocaust Remembrance organization. At 10 a.m. on Yom Hashoah sirens are sounded for one minute throughout the country and it is customary to stand in silence. Flags are flown at half mast and TV and radio broadcasts are devoted to the subject.
Customs
Yom Hashoah is an ordinary business day but many Israeli restaurants and places of entertainment close early in the eve of the day till the next evening.
From: https://info.goisrael.com/en/holocaust-remembrance-day-286911