Weather will likely play an important role when you plan your trip to Washington 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 July, with an average temperature of 17°C, while the coldest months are February and January, with an average of -4°C. The snowiest months in Washington Island are January, March, April and February, with each month seeing an average of 22 cm of snowfall.