The next upcoming Shavuot starts on sundown of May 16th ending at sundown on Tuesday May 18th, 2021.
People will celebrate the day by attending special prayer service all night Torah studying as well as having traditional meals with the consumption of milk and cheese and the requirement of time off from work. Some will decorate their homes and synagogues with greenery.
This day celebrates the reveling to the Israelites at Mount Sinai by God to Moses and the Israelites the Five Books of the Torah. The day also marks the wheat harvest in Israel.