Not sure if you know about some web sites that you can use to plan for weather for future trips.
Here is a website that you can check for destination, even enroute weather that shows month by month what the weather has been in the past. Notice I chose Dutch Harbor Alaska-chart lists the weather from 1951 thru 2005. Looks like the chances for good weather would be June or July...
Just choose the home page and type in where you would like to see.
This next link will show you the average percentages of different types of weather. Once again Dutch Harbor is the example. Notice that the average rain fall lowest is once again June, July & August:
This next link allows you to click on the pull down on the month /date and choose a date in the future for instance check out Sep. 2018 for Dutch Harbor:
I've used these sites to plan my flight when I bought my flying RV-6 for the return flight to Alaska. I knew I was going to fly it on a certain day, it worked beautiful for the flight up the coast of Canada!
Hopefully you can use some of these to plan a future flight for yourself!