How can clouds change color based on time of day?

I’m trying to create clouds that change color depending on the time of day so it looks realistic.


Unrealistic:

Realistic:

I’ve read through all the devforum posts and cannot find anything about this topic.

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The simplest way would be to tie the clock time directly to the RGB color of the clouds:

local lighting = game:GetService("Lighting")
local clouds = workspace.Terrain.Clouds

local function Update()
	local hour = lighting.ClockTime

	-- will be be 12 at midnight, 0 at noon, and 12 again at 24:00
	local howLowIsTheSun = math.abs(hour - 12)

	-- will be 0 at midnight, 1 at noon 
	local brightness = (12 - howLowIsTheSun) / 12
	
	-- will be black at midnight, white at noon
	clouds.Color = Color3.new(brightness, brightness, brightness)
end

lighting:GetPropertyChangedSignal("ClockTime"):Connect(Update)
Update()

A more in depth way would involve changing the equation to be more interesting, possibly to use a ColorSequence | Roblox Creator Documentation or something similar. That would let you do stuff like make the clouds pink at sunset, etc.

2 Likes

Here’s that fancier option, for fun!

local lighting = game:GetService("Lighting")
local clouds = workspace.Terrain.Clouds

-- ColorSequence stuff stolen directly from https://developer.roblox.com/en-us/api-reference/datatype/ColorSequence

-- first and last colors should probably match!
local cloudColors = ColorSequence.new{
	ColorSequenceKeypoint.new(0, Color3.new(0, 0, 0)),		-- black at midnight
	ColorSequenceKeypoint.new(0.25, Color3.new(0, 0, 1)),	-- blue at 6:00 AM
	ColorSequenceKeypoint.new(0.5, Color3.new(1, 1, 1)),	-- white at noon
	ColorSequenceKeypoint.new(0.75, Color3.new(1, 0, 0)),	-- red at 6:00 PM
	ColorSequenceKeypoint.new(1, Color3.new(0, 0, 0))		-- black at midnight again
}

function evalCS(cs, time)
	-- If we are at 0 or 1, return the first or last value respectively
	if time == 0 then return cs.Keypoints[1].Value end
	if time == 1 then return cs.Keypoints[#cs.Keypoints].Value end
	-- Step through each sequential pair of keypoints and see if alpha
	-- lies between the points' time values.
	for i = 1, #cs.Keypoints - 1 do
		local this = cs.Keypoints[i]
		local next = cs.Keypoints[i + 1]
		if time >= this.Time and time < next.Time then
			-- Calculate how far alpha lies between the points
			local alpha = (time - this.Time) / (next.Time - this.Time)
			-- Evaluate the real value between the points using alpha
			return Color3.new(
				(next.Value.R - this.Value.R) * alpha + this.Value.R,
				(next.Value.G - this.Value.G) * alpha + this.Value.G,
				(next.Value.B - this.Value.B) * alpha + this.Value.B
			)
		end
	end
end

local function Update()
	clouds.Color = evalCS(cloudColors, lighting.ClockTime / 24)
end

lighting:GetPropertyChangedSignal("ClockTime"):Connect(Update)
Update()
9 Likes