What it usually means
A rainbow needs two things that rarely seem to belong together: rain and sunlight. It appears only when both are present, with the sun behind you and the rain ahead. Dreams about rainbows usually draw on that meeting: hope arriving in the middle of difficulty, or two opposites coming together for a moment.
Hope is the main theme. Rainbow dreams often come after a hard period, as a sign that the storm is ending. They tend to leave a light, uplifted feeling that lasts into the morning.
Promise is close to hope. In the Bible, the rainbow is the sign God gives to Noah after the flood, a promise that the waters will not destroy the world again. Many people still feel a rainbow as a kind of reassurance, whatever their beliefs.
Rainbows are also fleeting. They cannot be held, and they move as you move. A dream of chasing a rainbow can be about longing for something just out of reach, or about a dream that keeps receding.
For many people the rainbow is also a sign of identity and pride, and a rainbow flag in a dream may simply carry those meanings — belonging, visibility, community.
Colour matters too. A rainbow contains the whole range of visible light. Dreams that dwell on its colours can be about diversity, joy, creativity, or a life with more variety than it has had lately.
What changes the meaning
A bright rainbow after rain. Hope after difficulty; relief and renewal.
A double rainbow. Exceptional good fortune; a doubled promise.
Chasing a rainbow. Pursuing something beautiful but hard to reach.
Finding the end of a rainbow. A wish fulfilled; or the realisation that the goal was an illusion.
A rainbow at night. Hope in an unexpected place; something rare and quiet.
A faded or broken rainbow. Hope fading; a promise only partly kept.
Walking on a rainbow. Idealism; a path that may not bear weight.
A rainbow over your home. Blessing on family life; peace after conflict.
A rainbow in a dark sky. Light in the middle of a hard situation.
Many rainbows. Joy, abundance, an unusually hopeful time.
A rainbow in water or a mirror. Hope seen indirectly, in reflection or memory.
A rainbow disappearing. A brief moment of grace that will not last, and does not need to.
When it keeps coming back
Recurring rainbow dreams often appear during recovery — after an illness, a loss, a crisis — as the mind keeps returning to the sense that something better is coming.
They also come when a person is bringing together parts of life that had been separate: work and family, past and present, two cultures, two sides of the self.
Children often draw rainbows, and adults who dream of them sometimes find themselves back in a childhood mood: simple joy, before things became complicated.
If you keep dreaming of rainbows, notice what the weather was before. The storm the dream remembers is often the one you are recovering from.
In Jungian terms
In Greek myth the rainbow was Iris, messenger of the gods, who travelled down it to carry their words to the human world. In Norse myth it was Bifröst, the burning bridge between the world of humans and the home of the gods. Both traditions saw the rainbow as a link between two realms that otherwise do not meet.
Jungian readers take the rainbow as an image of such a joining: sun and rain, light and water, the conscious and the unconscious meeting for a moment in a form neither could make alone. It cannot be held, because it exists only while both sides are present.
That is what a rainbow dream often marks, more than any promise of good luck: not the end of the rain, but the moment light reaches it.