Just like rdsx28 said, make sure you have DING! loaded on your PC so you will know immediately when fares are released.
The trend for Southwest has been that they release new fares approximatley 110 days from the last date available to purchase a reservation. For example the last date available to purchase fares is Oct. 27th. Go back 110 days in the calendar; which would be July 10th. Fares should be released around that time. But as previously mentioned you'll want to check everyday the closer you get to July.
Good luck and hope you get a great fare!