Weather will likely play an important role when you plan your trip to Adak Island, but bear in mind that cheaper options are usually available when the weather isn't as good. The hottest months are usually August and September, with an average temperature of 9°C, while the coldest months are January and February, with an average of 2°C. The snowiest months in Adak Island are January, March, December and February, with each month seeing an average of 64 cm of snowfall.