I just got an email re: A Westjet summer sale. According to them, there are 3 time frames and Destinations for which sales exist.
Canada & U.S - August 8 to Feb 15
Mexico & Caribbean - August 1 to Dec 19
Europe - September 6 - Feb 15
https://www.westjet.com/en-ca/index
Canada & U.S - August 8 to Feb 15
Mexico & Caribbean - August 1 to Dec 19
Europe - September 6 - Feb 15
https://www.westjet.com/en-ca/index