I am getting the error in the above statement.
I have tried adding apostrophes for each value but still the same error.

GradeHistoryDates holds a date, but is declared as a Variant

Code:
            strSQL = "UPDATE tbl_Grade SET " & _
                "Yellow = " & GradeHistoryDates(0) & ", " & _
                "Orange = " & GradeHistoryDates(1) & ", " & _
                "Green = " & GradeHistoryDates(2) & ", " & _
                "GreenBlack = " & GradeHistoryDates(3) & ", " & _
                "Blue = " & GradeHistoryDates(4) & ", " & _
                "BlueBlack = " & GradeHistoryDates(5) & ", " & _
                "Brown = " & GradeHistoryDates(6) & ", " & _
                "First = " & GradeHistoryDates(7) & ", " & _
                "Second = " & GradeHistoryDates(8) & ", " & _
                "Third = " & GradeHistoryDates(9) & ", " & _
                "Fourth = " & GradeHistoryDates(10) & ", " & _
                "Fifth = " & GradeHistoryDates(11) & ", " & _
                "Sixth = " & GradeHistoryDates(12) & ", " & _
                "Seventh = " & GradeHistoryDates(13) & ", " & _
                "Eighth = " & GradeHistoryDates(14) & ", " & _
            "Where Memb_ID = " & MembID
                  
                Debug.Print strSQL
        cn.Execute strSQL