Despite their splendour, rainbows usually get, “second billing” next to the falls, especially to first time viewers of the falls. On any bright sunny day (they’ve been few and far between so far, this winter) you are guaranteed a rainbow if you stand in the right spot. When your back is to the sun, rainbows are seen in the mist created by the falls. The sun shines through the water droplets reflecting the light into the colours of the rainbow.
Because the sun rises in the east, rainbows are seen in the morning from the United States side. As the sun gets higher in the day, rainbows are seen on the Canadian side.