Planar reflections not reflecting sky

Hello,
Planar reflections is not reflecting the sky for some reason. I’m not using any Skydome, it’s just the Atmospheric Fog (which is turned on, on the Scene Capture params.
Could this be happening because there is nothing behind the fog thus Planar reflections not seeing it, as the fog is visible on the mountain meshes?

https://s16.postimg.org/5pn4b7mwl/Highres_Screenshot00000.png

Hi Kristusea,

Your assumptions are correct that you will need a sky sphere to have something to reflect. If you need something there that is still on the dark side but reflected you can try a sky sphere with a darker material or night sky or whatever fits your needs.

Tim