Of course, there are sunny days in Alaska, sometimes reaching 75 F or more. But, on most days you can expect temperatures to be in the 50 s and 60 s, perhaps dipping into the 40 s during really foul weather. Strong winds are uncommon during summer so heavy wave action should be minimal. The research is conducted among islands that are situated far enough from the ocean that the effects of ocean swells and surf are generally not felt - seasickness is rarely a problem. Summer sea temperature hovers around 45 F so don't plan on doing much swimming unless you have the blood of a polar bear.
Divers usually wear drysuits in Alaska.
Check out the weather and aurora forecasts links for more information. The Alaska Whale Foundation provides all the equipment except personal items such as sleeping bags, clothing, etc. They will provide you with a float coat and life jacket. A complete personal equipment checklist will be provided upon confirmation of your reservation. All meals beginning with lunch the first day and ending with lunch the last day will be provided.