If they are going to have a promo, they are often announced in mid/late January and run through May. They always have some blackout dates usually in March.
But having said that, this year they are opening the Rise of the Resistance attraction in Star Wars land. So a lot depends on whether
Disneyland blocks out the lower tier annual passholders the way they did this year. I'm thinking since the crowds were so low this summer they probably won't block any passes so it should be crowded, at least initially, due to the novelty. So that kind of works against the idea that they will have any discounts this coming winter/spring. But you never know. Star Wars has not worked out the way Disney had hoped in the parks and the new attraction might be a bust. Only time will tell.