Due to its vast size, Alaska's climate conditions vary. In general, tour itineraries start in May and last through September.
The summer months of June, July and August are the high season when most people visit Alaska. In August, the weather is warmer and often wetter. Days are long in the summer, especially in June when daylight can last for up to 23 hours.
May and September are considered the shoulder season when prices lower and crowds lessen, but the weather is damper and can be cooler. In May, things are still defrosting and some tourist activities may be closed. If you consider travel in September, be sure to pack accordingly for chillier temperatures as you enjoy the vivid autumnal foliage.