I saw a faint rainbow, but no rain. Is this possible?

It seems like just about anything is possible when it comes to the weather. 

Although we typically see a rainbow during a rain shower when the sun peaks through the clouds, it is possible to see a rainbow when no rain is falling. Remember a rainbow occurs when the light from the sun enters a drop of water and is bent (refracted) and reflected back to your eye. But the drop of water doesn’t necessarily have to be a large raindrop; tiny droplets in a cloud can also reflect sunlight to produce a rainbow.

It should be noted that there may have been rain evaporating before reaching the ground.  The clouds high in the atmosphere may also be in the form of ice crystals, which can also produce a rainbow.