When is best time to cruise Alaska? The cruising season in Alaska only lasts about five or six months from about May to September. The “off season” only lasts for a few weeks at either end (May and September). May and September are probably also the best couple months to cruise to Alaska as the ships will be a little quieter. The warmest and longest days will be in June and July.
If you are interested in whale watching then the summer is is the best for seeing humpback whales. If you want to see Killer Whales (Orcas), the best months are June or July.