The Pack Creek bears (excursions out of Juneau) were out that late, but nobody was running tours due to weather last year. Sitka would be a fun option to try (one that I hadn't considered before.)
(Good advice about calling a few vendors and asking. Many operators will have to charge a late cancel penalty to cover the cost of usage permits.)
For all locations, the bear visibility will be directly affected by the timing of the salmon runs. If fish spawn there, they will come...