Can't say I'm a ton of help, but I worked in Petersburg (on the panhandle part of Alaska.) for a summer and spent a day in Juneau.

It snowed a couple inches the first week and was 70 degrees during the day the rest of the summer after that. Getting dark just after midnight and the sun coming back up at 3:30-4:00ish was pretty cool too.

Yep - mosquito repellant is good. ...and there's lots of bears (black, in the SE, at least) running around, so watch your back and make lots of noise!