Bring clothing you can layer. You'll want to be outdoors with binoculars the day you spend cruising near the glacier, but it can be cold. Bring gloves and a hat, too. You may want to stand there for hours.
Also, when you get off the ship in a port, the weather can go from cool to warm, and layered clothing is the way to go there, too. Bring a rain coat or rain repellent jacket.
Be prepared to be able to read a newspaper out on deck at 11pm! The sky never really gets dark that time of year.
Well I am going Alaska in May - 1st cruise and 1st time in AK. I will let you know what my experience was when I return. I am going on the Coral Princess. It will be interesting to compare the differnces between the cruiselines as well!
We are sailing on Carnival out of Anchorage on July 9. I am anxious to see the sun all evening. That will be a highlight for me!
The sun goes down, but the sky never gets dark. It's sort of dusk until the sun comes up again. We had to pin the drapes of our Anchorage hotel room closed the night before the cruise, to try to get some sleep in a darkened room.
Tekdiva - my Alaskan cruise was in May - prepare for a range of weather - it was hot in Vancouver when we left (shorts weather) but there were places with snow, and there was ice in Glacier Bay. Layers of clothes, hat, gloves and a good raincoat that can be worn over a heavy sweater are essential. But again the evenings are long. I have a great sunset picture taken at midnight