How do you set the hour of the day on the Sims 2?

By waiting till about roughly 8PM. Or if you would like to view the household @ nighttime in build/buy mode, there is a circle divided into a moon and a sun like icon. Clicking the icons will change it to the appropriate time of day. The day/night circle tool is located to the left of where all the objects you can buy are, near the Eyedropper Tool.