Horror part of the tribulation starts in June 2012?Read this page I found online.
http://www.adishakti.org/mayan_end_times_prophecy_12-21-2012.htm
Both the Hopis and Mayans recognize that we are approaching the end of a World Age. But the former, however, offer no time limits, while the latter have a calendar system whose grand Thirteen Baktun cycle will end either on December 24, 2011 or June 6, 2012 (depending on your method of calculation). In both cases, however, the Hopi and Mayan elders do not prophesy that everything will come to an end. Rather, this is a time of transition from one World Age into another. The message they give concerns our making a choice of how we enter the future ahead. Our moving through with either resistance or acceptance will determine whether the transition will happen with cataclysmic changes or gradual peace and tranquility. The same theme can be found reflected in the prophecies of many other Native American visionaries from Black Elk to Sun Bear.
Some say Mayan calendar points to December. 2012. But maybe the June 6th would be more accurate. Because Obama was sworn in on Jan 19 or 20th. And based on Mayan or Hebrew calendar, each year has 360 days. This means 3 years and a half from Jan 20 of 2009 is around June 3rd to June 6th of 2012 if each year has only 360 days.