The National Museum of African American History and Culture has launched a new set of visitation guidelines for 2019, including the introduction of peak and off-peak seasons.
From March through August, the museum will require timed-entry passes for the peak season when visitation is highest. During off-peak season, September- February, when visitation is lowest, visitors will be able to enter the museum without passes.
Museum passes are required every weekend throughout the year. More information is here.