A rainbow will usually be a sign of hope, signalling the end of gloom and the re-entry of the warming sun. Since the sun may be a symbol of the self, the rainbow may symbolize bridging the gap between yourself as you are and your true self. (But for some African peoples the rainbow is a bad sign, since it means the end of a rainstorm, and drought means death.)
Occurring after the transfigurative rains, the Rainbow represents hope and reward for prolonged sacrifice. Accordingly, the rainbow is the bridge to personal illumination. Consequently, since the rainbow contains all the primary colors, our unconscious may be illustrating the paramount gift available to humanity is the embodiment of the full spectrum of our emotions. Furthermore, since a rainbow is a direct refraction of sunlight, we may interpret the dream rainbow as pertaining to the arrangement of wisdom, guidance and perceptive clarity in our waking life.