Fog color script issue?

I have this code here that changes the fog color with the time of day, but it is not working the way it should.

It turns black correctly, but the fog doesn't turn blue.

`function onLightingChanged()

if game.Lighting.TimeOfDay == "6:00:00" then
    game.Lighting.FogColor = Color3.new(180/255, 255/255, 234/255)  --Day
end

if game.Lighting.TimeOfDay == "18:00:00" then
    game.Lighting.FogColor = Color3.new(0/255, 0/255, 0/255) --Night
end

end`

local Lighting = game:GetService("Lighting")

Lighting.LightingChanged:connect(onLightingChanged)