https://www.southwest.com/html/promo...le-150602.html
Purchase from June 2 through June 4, 2015, 11:59 p.m. for the respective time zone of the originating city.
Travel August 24 through December 16, 2015.
Blackout Dates Apply: September 3-5, September 7, and November 20 - December 1, 2015.
Travel not valid on Fridays and Sundays. Travel to/from Florida or Nevada is valid only on Tuesdays & Wednesdays. Travel to/from San Juan, Puerto Rico is valid only Mondays through Thursdays.
Fares valid on nonstop service only. 
(not distance based anymore. this doubles most of my flight costs compared to other sales years.)
Fares not available to/from Portland, ME.
Seats and days are limited. Fares may vary by destination, flight, and day of week and won't be available on some flights that operate during very busy travel times and holiday periods.