July and August are always the peak months. Days are very, very long, with only a couple of twilight hours in the wee hours of the morning. These months are also the driest, although you will want to pack a lightweight rain jacket anyway. The days are shorter and cooler in May and June, as well as September, and the cruise fares usually reflect this change in the seasons. Alaska loses about 5 minutes of light daily, so you can see why the summers are so short. Enjoy your cruise, we went in July 1999 and had a wonderful time. We live in Seattle, so were familiar with the unpredictable cooler weather. It will be surprisingly warm inside Glacier Bay.
I've done Alaska three times, one in May, and two in June, have had anything from cool and rainy/cloudy to sunny where I was wearing shorts. This is an absolutley fabulous trip, and I plan to go again in August 2002!
If you are not afraid of cool weather, the latter part of May is great for beautiful
mountain scenery--lots of snow covered peaks and the glaciers are at their
finest. We have made four trips at different times of the summer, but we are
going back again next May, 2002.
We went in mid June and it was wonderful. Nice warm days and plenty of daylight/sunshine. The mountains were gorgeous all snow capped and we had calm seas. We are sailing this year in July for a change in the fishing season. June and July are suppose to be the driest months.
Have sailed to Alaska 5 times, most recently in Mid sept, I suggest mid June as we have always had good weather. If you wait until August or Sept, most of the snow will be gone.(although we had cool, but fantastic weather on on our sept sailing)(residents in Ak told us we had the nicest week of weather the whole summer up there.(no rain at all, just clear sunny and slightly cool days, but things were rather quite as the season was winding down . We will be back to Alaska for our 6th Alaska sailing on June 23rd in 2002 on the Mercury.
Enjoy your cruise, the cool weather is just wonderful and really make you want to get out and enjoy the outdoor activities.