The construction of the new events center will make parking at the Arena a bit different then past years. The school district has info here and here. Take a look at this map and plan according.

sf.k12.sd.us

Sioux Falls High School Graduation: May 19 at the Sioux Falls Arena
Roosevelt HS - 1:00 PM
Washington HS - 4:00 PM
Lincoln HS - 7:00 PM