This photo was taken at three in the afternoon in bright, warm sunlight. In fact, the sky and the grass looked a little overexposed and the tree a little underexposed.
Post processing included levels, channel mixing, curves, HSL, and more curves. This revealed quite a bit of noise in the sky so NeatImage was used to get rid of it. Initially the image had been sharpened, but the thin line 'ghosting' that occurs became much too noticable and the unsharpened image was used.