The nearest expiration date for PJM PEPCO Zone Peak Calendar-Month Day-Ahead LMP 5 MW Futures (Jun 2014) is Jul 1, 2014.
The best time to sell a futures contract is when you've already made money on the investment, but still have plenty of time left before the expiration date. Thus, a good option would be to sell PJM PEPCO Zone Peak Calendar-Month Day-Ahead LMP 5 MW Futures (Jun 2014) before Jul 1, 2014.