The sky is something you have to look up to see and in dreams asks you to adopt a better view of the subject matter of the dream – look up to it rather than looking down on it.
The sky is often used in dreams to introduce the color blue. A blue sky represents your philosophy of life with regard to the subject matter of the dream and attempts to get you to lighten up. White fluffy clouds in a blue sky also heal a negative philosophy of life by restoring confidence (white) for the future. When the sun is prominent in the dream it is also very healing and encourages creativity (sun) in dealing with your current challenges. See blue for more.