As marketers "entering the conversation already taking place in the customer's mind" (Robert Collier), we know that conversation includes the current season and holidays This makes the seasons and holidays great "hooks" for advertising and promotions.
Holidays and seasons are “a natural” for promotions
A very straightforward approach for promotions is to tie into a holiday or season.
How holiday promotions can get a customer’s attention
Tying a promotion into a holiday can be an effective way to get a customer's attention. Holidays can also provide a "reason why" for a promotion.