Shemini Atzeret for the year 2021 is celebrated/ observed on sundown of Monday, September 27th ending at sundown on Tuesday, September 28.
Shemini Atzeret, with Shemini meaning eighth follows the seven day holiday of Sukkot and can be considered the eighth day of Sukkot in many ways but not all ways. This day on the Hebrew calendar falls on 22 Tishrei. Many in Israel will celebrate Shemini Atzeret and Simchat Torah on the same day, however others in the rest of the world will celebrate them one day after the other making them two separate holidays with Simchat Torah falling on 23 Tishrei.
Days to the start of Shemini Atzeret 2021
Tuesday, September 28th is day number 271 of the 2021 calendar year with 1 year, 10 months, 15 days until Shemini Atzeret 2021.