You need not check for color , if your sure that your column will remain constant (4th Column)
then get the column name and display tooltip whenever mouse hover on this column..
private void GridView_MouseHover(object sender, EventArgs e)
String columnName = GridView.HeaderRow.Cells[i].Text;
if(columnName == yourdesiredcolumnName)
GridView.CurrentCell.ToolTipText = "Sunday";
1.I know your column index will change often, but your column name will not change rite.
so you can get the column name from the Gridcontrol and display tooltip only for this column
let me know if have any issue.