Weather is probably a major factor when you plan your trip to Clatskanie, and keep 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 temp of 62°F, while the coldest months are December and February with an average of 40°F. The rainiest months in Clatskanie are December, November, January, and March, with each month seeing an average of 8 inches of rainfall.