To see a rainbow in your dream represents hope, success and good fortune in the form of money, prestige, or fame. The rainbow is also seen as a bridge between your earthly, grounded self and the higher, spiritual self. It refers to joy and happiness in your relationship. Alternatively, the rainbow implies that your troubles are almost over. Good will come out of your issues. Just hang in there. In the western culture, the rainbow is a symbol for gay pride.
To see a rainbow at night or a lunar rainbow in your dream is symbolic of a spiritual or emotional connection within your personal relationship or religious beliefs. Dreaming of an all white rainbow signifies heightened spirituality and purity.
To dream that something is rainbow coloured implies that you need to see things in a more positive light. You need to be more optimistic. Also consider the significance of the object.
To dream that you have rainbow coloured hair refers to your light-hearted and carefree nature. You are headed in a positive spiritual direction.