One thing about storing cedar outside if you are planing on staining. Is that it should be stored in a way that it will dry evenly. One way of doing so is by doing layers of sticks so that air can flow in between the wood. Keeping it elevated above wet ground is also important to avoid any kind of mold or algae from forming on the surface.
Keeping it out of the sun is important as it will fade quickly in the UV light to a greyer bleached look. Depending on preference you would want to cover your cedar with a tarp or other means.