Rainbow's little sister, the moonbow can be seen ever so faintly during the night. It appears when moon light gets reflected by moist clouds in the atmosphere. Since the light from The Moon is much weaker, the resulting moonbow is first of all much smaller and its colors can be very hard to discern. This is why they are also called white rainbows. Another thing is the location. You need a region with lots of fog and general water vapors. Waterfalls are the perfect places and some magnificent pictures can be taken there during the night.