Easter is not on a fixed date every year, but is tied to the full Moon and the vernal equinox. Christians in western countries that use the the Gregorian calendar (like the United States) celebrate Easter on the first Sunday after the paschal full Moon, which is on or just after the vernal equinox. For simplicity, the equinox is considered March 21.
Easter Sunday is on the following dates:
April 4, 2010
April 24. 2011
April 8, 2012
March 31, 2013
April 20, 2014
April 5, 2015
March 27, 2016
