Oranienburg can be visited year-round; the memorial sites are open throughout the year except for a few public holidays. Summer is the most pleasant for exploring the Schlosspark along the Havel, and the outdoor sections of the Sachsenhausen memorial are more accessible in dry weather. Spring and autumn are also fine — Brandenburg's flat landscape means there is rarely extreme weather, though winter visits to the memorial can feel particularly austere, which some visitors find appropriate.
The Sachsenhausen memorial site closes on Mondays during October through March, so confirm opening times if planning a winter visit.