If your dream takes place outdoors, this symbolizes freedom, tranquility, restoration, and renewal. It may also mean that you want to fully experience and express your feelings and instincts.
Beyond you, outside of your inner experience
The part of your life where you interact with others or make impressions on others
A house usually represent you, inside the house represents your inner life (your thoughts, feelings, etc.), and so things happening outdoors would represent things going on around you. Depending on the particular kind of outdoor setting in your dream, it could also represent a particular real place, or a particular set of feelings (like a cemetery could represent loss or sadness).