How do waterfalls generate mist and rainbow effects?

Waterfalls often create a cloud of spray because the water hits rock or the pool below at high speed and breaks into fine droplets. That mist can drift into the air and make the area feel cool and humid. If sunlight shines through the droplets, refraction and reflection can produce a rainbow. This is why bright waterfall rainbows are often seen late morning or afternoon when the sun angle is favorable.