Just like we can see a rainbow in the daytime , similarly you can also see them in the night .These lunar rainbows are also called Moonbow . Moonbow is a rare phenomena .It happens when the moonlight instead of sunlight is reflected off water droplets in the air.It can be seen when there is full moon , in places where there is high humidity , mist or rain. It's colors appear white to the naked eye it can only be seen in the long exposure photograph.