Microsoft has been coy about the exact release date of Windows 10 thus far, telling us only to expect a launch this summer. AMD may have tipped Redmond's hand, however. During the question-and-answer segment of AMD's latest earnings call, CEO Lisa Su told an analyst that Windows 10 will launch "at the end of July," according to Seeking Alpha's transcript of the call.
Microsoft's Build developer conference kicks off next week, so it's possible we'll learn more about the release timeline then. For now, it seems like we have a little ways to go before the new OS becomes available to the public.