On the eve of HTC's much-teased February 19th event, multiple sources are converging on March 14th as the announcement date for Samsung's next flagship Galaxy S device. Originally alluded to by Eldar Murtazin of mobile-review and later corroborated by unnamed sources of The Verge, the Galaxy S4 will "definitely" be announced at a Samsung event on March 14th. The rumored event is expected to take place in the U.S., but it's unclear at this time what city will be hosting such an announcement.
As for the design and details of the Galaxy S4, we really don't have much to go on. Again reported by sources of The Verge, the new device may follow the design language of what we will see as the Galaxy Note 8.0 at MWC. Although the leaks we've seen thus far of that device are apparently far off from what the final design is.
With all of that being said, we'll only know the announcement date for sure when we hear it directly from Samsung.
Source: The Verge