Not Always Getting Expected Outcome When Comparing Calendar Objects

I am writing a short program to find the zodiac of a given birth date. I am checking to see if a calendar object falls between to other objects to see if the date falls within a certain zodiac sign. To accomplish this, I have the user enter a date, then that date is compared to dates taken from an array. The problem is sometimes the comparison doesnt seem to work work, giving the wrong zodiac. For example if I enter 03/28/1968, it finds Aries, as expected. However if I enter 03/20/1968, it returns Aries also, when it should return Pisces. Here is the sample code.

private static String determineSign(Date birthdate, String[][] zodiac) throws ParseException {
// TODO Auto-generated method stub
Date date = birthdate;
for (int row = 0; row < zodiac.length; row++)
{
DateFormat date3 = new SimpleDateFormat("MM/dd");
Calendar compDate3 = Calendar.getInstance();

[Code] .....

This is the class that creates the table used for the zodiac dates -

public class ZodiacTable {
static final int ROWS = 12;
static final int COLUMNS = 3;
//private ArrayList<String> zodiacNames;
private String[][] zodiacNames;

[Code] ....

I cant seem to see why it returns the wrong zodiac..