From what I understand, skylights only add color to the overall scene. I’m not entirely sure about this, but my method was to just raise the environment color in lightmass to the sky color, which illuminates shadowed areas and bakes the result directly into the lightmaps (which need to be baked anyways) without adding anything to the runtime cost (not that it would be much, but still). Also, I heard skylights will basically destroy your contrast and should generally be avoided if you’re going for a more realistic look.