[Switch doesn't working correctly]

Thanks all!

Everything was solved correcly ^^

[Switch doesn't working correctly]

Hi,

I'm making a code for determining the astrological sign of anyone.
The code receives a date in this format "YYYY-MM-DD" and strips that string in year, month and day.

So I've wrotten this function:

    //determinar signo
    public function Determinar(){
        switch ($this->month){
            case 01:
                if ($this->day <= 19){
                    $this->signo = "Capricornio";
                } else {
                    $this->signo = "Acuario";
                }
            break;
            case 02:
                if ($this->day <= 18){
                    $this->signo = "Acuario";
                } else {
                    $this->signo = "Piscis";
                }
            break;
            case 03:
                if ($this->day <= 20){
                    $this->signo = "Piscis";
                } else {
                    $this->signo = "Aries";
                }
            break;
            case 04:
                if ($this->day <= 20){
                    $this->signo = "Aries";
                } else {
                    $this->signo = "Tauro";
                }
            break;
            case 05:
                if ($this->day <= 20){
                    $this->signo = "Tauro";
                } else {
                    $this->signo = "Geminis";
                }
            break;
            case 06:
                if ($this->day <= 20){
                    $this->signo = "Geminis";
                } else {
                    $this->signo = "Cancer";
                }
            break;
            case 07:
                if ($this->day <= 20){
                    $this->signo = "Cancer";
                } else {
                    $this->signo = "Leo";
                }
            break;
            case 08:
                if ($this->day <= 21){
                    $this->signo = "Leo";
                } else {
                    $this->signo = "Virgo";
                }
            break;
            case 09:
                if ($this->day <= 22){
                    $this->signo = "Virgo";
                } else {
                    $this->signo = "Libra";
                }
            break;
            case 10:
                if ($this->day <= 22){
                    $this->signo = "Libra";
                } else {
                    $this->signo = "Escorpio";
                }
            break;
            case 11:
                if ($this->day <= 22){
                    $this->signo = "Escorpio";
                } else {
                    $this->signo = "Sagitario";
                }
            break;
            case 12:
                if ($this->day <= 20){
                    $this->signo = "Sagitario";
                } else {
                    $this->signo = "Capricornio";
                }
            break;
        }
    }

In this switch, cases 01 to 07 and 10 to 12 are working correctly.
But cases 08 and 09 doesn't works.

I can't find the problem/error, syntax seems to be correct