You can do this in the
RowDataBound
event code.
For e.g.
Protected void myGrid_RowDataBound(object sender, GridViewRowEventArgs e)
{
if (e.Row.RowType == DataControlRowType.DataRow)
{
if (e.Row.Cells[month].Text == "March")
{
e.Row.Cells[1].ForeColor = System.Drawing.Color.Red;
}
}
}