Hug a GI Day is celebrated on March 4th of each year. The staff at National Whatever day were unable to discover the origin of Hug a GI Day.
G.I. is a noun used to describe members of the U.S. armed forces or items of their equipment. The term is now used as an initialism of “Government Issue” (or often incorrectly “General Infantry”), but originally referred to galvanized iron.
The letters “G.I.” were used to denote equipment made from galvanized iron, such as metal trash cans, in U.S. Army inventories and supply records. During World War I, U.S. soldiers sardonically referred to incoming German artillery shells as “GI cans.” In that same war, “G.I.” started being interpreted as “Government Issue” and said as an adjective of anything having to do with the Army.