Personal leave must be used by June 30th.  If you do not use the leave by June 30th, you will lose the time.  EmpCenter shows this in the leave balances tab. 

If you have leave available in your Personal Leave Bank at the beginning of June, EmpCenter shows that if you do not use the leave by the end of the month, you will lose the leave:

personal leave bank showing amount that will clear at the end of june

If you click on the Show Details link you will see that EmpCenter is set to "Clear" the bank on June 30th:

personal leave bank details showing the clearing happening on june 30th

You are still able to use the time during the month of June - up to and including on the 30th:

personal leave entered on timesheet on June 30th

Any balance remaining at the end of the day on the 30th will clear from your leave bank.