The day-long event will take place at Microsoft's Redmond, Wash. campus, and will provide "more details on the Windows 10 consumer experience," according to the invitation. Previously, Microsoft had promised that it would disclose the upcoming operating system's consumer-side features and focus in early 2015.
Microsoft will also use the event to issue another Windows 10 preview to replace the string it has released since the original Sept. 30 launch of the enterprise-centric Technical Preview.
That September event was held in San Francisco, and featured a pair of top Windows executives, Terry Myerson, who leads the company's operating systems group, and Joe Belfiore, a vice president responsible for Windows' design.
Myerson and Belfiore will certainly present at the January event as well. CEO Satya Nadella will also participate, according to Microsoft watcher and ZDNet blogger Mary Jo Foley. Microsoft did not immediately reply to Computerworld's questions about what part Nadella will play, if any.
Foley also asserted that at least part of the event will be publicly webcast, which would be in sync with some of Microsoft's 2014 launches, including March's debut of Office for iPad and May's introduction of the Surface Pro 3. Nadella participated in both.
September's Windows 10 unveiling, however, was not webcast, although Microsoft later made a recorded version available.
Analysts have been generally upbeat about what Microsoft has shown so far of Windows 10, although some have expressed concerns about its chances of turning around a stagnant PC industry if falling hardware prices decimate the premium part of the business.
Microsoft's scheduling of a larger Windows 10 event in January -- by the scant details of the invitation, it will be both larger and longer than the September debut -- fits with what Gartner analyst Michael Silver said in October.
"Microsoft can't make a big bang and talk about a new version of Windows in September with the holidays coming and consumers deciding that 'if Windows 10 is coming, I'm just going to wait and not buy a PC,'" Silver said then.
At one point Microsoft was pegging the official launch of Windows 10 as mid-2015. Last week, however, chief operating officer Kevin Turner told a technology conference's attendees that it would be "late summer and early fall." Today Turner modified that to "early fall" in an interview with Japan's The Nikkei.