In some places where electricity costs more during certain times of the day it would be best to run the dishwasher after lunch or when you get home from work.
During this time the electricity grid is not working so hard to deliver electricity so some places have cheaper electricity rates during those hours.
However in my area it makes no difference because electricity costs the same amount of money no matter what time of day or night I use the electricity.
But if my electricity rates were cheaper at night then I would run the dishwasher at night before going to bed.