Microsoft tells workers to prepare to return to the office.

Microsoft told employees that they will need to return to office next month, transitioning back to its corporate campus for the first time since the Omicron coronavirus variant tore through the nation.

The company has long said it would embrace a hybrid work environment, with most employees able to work from home up to 50 percent of the time. In a Monday morning blog post focused on its headquarters near Seattle, Chris Capossela, an executive, said that starting Feb. 28, “employees will have 30 days to make adjustments to their routines and adopt the working preferences they’ve agreed upon with their managers.”

Mr. Capossela cited the high vaccination rates in King County, where most employees live, and declining hospitalizations and deaths in the state as factors in the decision. Residents in King County, which includes Seattle, are among the most vaccinated in the country, with more than 91 percent of those who are 5 or older having received at least one shot.

While the announcement was focused on the company’s home state, where most of Microsoft’s employees are based, Mr. Capossela said the company’s Bay Area sites “will fully open on Feb. 28, and we anticipate many of our other U.S. locations will follow suit as conditions allow.”