On Thursday May 14, 2015 (tomorrow morning), Southwest's schedule should open for sale through January 4, 2016. Recent extensions have been happening between 5:30 AM and 6:15 AM Central Time.
This is the big one, covering Thanksgiving, Christmas, and New Year's Day. Expect the new dates to show up between 5:30 AM and 6:15 AM Central Time Thursday May 14.
In the past I have found low fares available for some Thanksgiving Wednesday and Monday flights at schedule opening, and that those fares often never return. Christmas fares may decrease later in the game. If you book with points you can re-fare to a lower points price later, with the excess points returning to your account.
This year you may not benefit from booking holiday travel at schedule opening. Two days ago Southwest surprised me with the largest fare increase I have ever seen, focusing on peak travel dates:
http://www.flyertalk.com/forum/south...-tomorrow.html
I expect peak holiday travel dates to have very high fares in this schedule release, as Southwest protects itself from possible increases in fuel cost between now and the end of the year. For non-peak fall travel you may want to gamble that Southwest will offer an anniversary sale starting June 9 or June 16. That's what I'm doing.
Be aware that the schedule opening may not activate on all Southwest's servers at the same time. Reloading the web page may put you on a different server, opening or perhaps even closing the schedule extension. Patience is required. Note: it is best not to log in first.
In some past schedule extensions, Standard Award seats did not become available immediately: They appeared later the same day.
Speaking of Standard Awards,
Thursday May 14 is also the very last day for you to create a Standard Award from any seed credits you have. On May 15 Southwest will convert your seed credit to points, at 1200 points per credit. It's decision time.
Standard awards are useful primarily for last-minute travel such as family emergencies. In those cases fares are high yet some flights are lightly loaded. Southwest is often willing to give you a Standard Award seat on one of those off-peak flights, even across the country. Any flight with a cash price of $150 or more each way is a candidate for using a Standard Award, but 80% or more of those flights will not have Standard Award availability. The important exception is flights past the deadline for purchase of Wanna Get Away fares. Almost all of those cost more than $150 and many of them have availability for Standard Awards. If you buy last-minute tickets regularly, you should consider creating Standard Awards using your seed credit(s) if you and your family members have them.
For more discussion, see
http://www.flyertalk.com/forum/south...14-2015-a.html
For information on future schedule extensions, see the travel tools page at
www.southwest.com/html/travel-tools/index.html