The Sky Light captures the distant parts of your level and applies that to the scene as a light. That means the sky's appearance and its lighting/reflections will match, even if your sky is coming from atmosphere, or layered clouds on top of a skybox, or distant mountains. You can also manually specify a cubemap to use. For any additional information, see the Unreal Sky Light documentation.

||Modes Tab|| > Lights > Sky Light

Light

Source Type – Whether to capture the distant scene and use it as the light source or to use the specified cubemap.

SLS Captured Scene – Construct the sky light from the captured scene.

SLS Specified Cubemap – Construct the sky light from the specified cubemap.

Cubemap – Specify the Cubemap to use for sky lighting if Source Type is set to SLS_SpecifiedCubemap.

Source Cubemap Angle – The angle to rotate the source cubemap when Source Type is set to SLS Specified Cubemap.

Intensity scale – The total energy that the light emits.

Light Color – The color that the light emits.

Affects World – When enabled (the default), the light contributes to the lighting in the level. Disabling it will stop the contribution of the light in the environment.

Cast Shadows – When enabled (the default), the light casts shadows. Turn this option off to disable shadow casting for the light.

Lower Hemisphere Is Solid Color – Whether all lighting from the lower hemisphere should be set to zero. This is useful to prevent leaking from the lower hemisphere.

Lower Hemisphere Color – The color that the lower hemisphere emits when Lower Hemisphere Is Solid Color  is enabled.