This 1024x1024px sky is a high quality custom rendering for terrestrial/earth scenes.It is specifically oriented towards the look of a wintery, approximately noon sky. I recommend turning down shadows for this sky to a low value. It is specifically modeled to fit either rain, snow, or hazy weather. It's appropriate for any dreary environment you may think of.
I have gone with 1024x1024px due to quality loss from the DDS format. The quality is virtually identical to the 2048x2048 version, I dare say even better due to the way DDS files are created.
The sun is visible directly above, there are no scrolling skies and no terrain floor (so it is not suitable for scenes where the terrain is missing).