National Museums of Kenya opening hours are 8.30 am every day while closing hours are 6.00 pm. The institution opens Monday to Sunday and including public holidays.
Since during public holidays many Kenyans have time to visit such places, National Museums of Kenya is forced to open to attract visitors.
Here is the summary of opening and closing hours:
8:30 am to 6:00 pm
Monday‐ Sunday (including Public Holidays)