System requirements:

Min: i7 2770k/ryzen 1200, 4gb RAM, Gtx 960/1050 Ti (for Eevee viewport, for Cycles it doesn’t matter that much); Recommended: i7 7700k/ryzen 1600, 8gb RAM, Gtx 1060 6GB.

Tested in Blender 2.92, Blender 2.93 LTS should be working fine too.

Important difference between Eevee and Cycles:

Cycles version doesn’t need Sunlamps for lighting, so turn them off if you plan to use Cycles. I created the shader in a way, the clouds will naturally cast shadows so when the sun is behind them, its light will be reduced or disappear and the scene will be darker in a realistic way.

Eevee works differently. It needs the lamps for sunlight to work so turn them on for Eevee.

Very good performance:

In Cycles, the shader can produce clear results at only 1 sample like a HDRI. It takes less time to load than a typical 8k or 16k HDRi while it has higher resolution thanks to it being procedurally generated. When rendering a scene, the sky is the fastest part to render.

In Eevee the shader compilation takes only 5-8 sec, after that it loads instantly. My rig has 1050 ti which tends to become overwhelmed in Eevee fairly quickly, but this shader runs quite good on it. With a little bit better card, viewport should be very fast too. The “Reduce to preview quality” slider can make viewport speed twice as fast, ideal for lower end cards.

General rule: Try not to type in custom numbers, don’t type numbers that are out of the slider’s range since it may break some features or lighting. If you did this, type a number that fits into the slider’s range.

I. General settings

1.) Time (total min):

This is used to control the height of the sun. Slide it to change the time of the day.

Known limitation: The drivers (that are used for the complex shading and animation of the scene and clouds) don’t refresh when you manually type in a number – this issue is 90% a Cycles problem, Eevee sometimes has a little delay too. If this happens, the clouds may have an unusual color or shape. I suspect this is because of low end GPU/PC I have so anything over a 1050 TI may improve or completely fixes this, as the faster Lite version doesn’t have this problem for me. Otherwise this can be easily fixed; the result is always consistent.

Fix a.)

Don’t type numbers, just slide the sliders.

Fix b.)

If you want to type in a number, press enter then type it again. This will refresh the lighting.

Fix c.)

Move any other slider (change any other settings) which will also refresh the lighting.

2.) Time (hour), time (min), day counter (total).

These help you know what time it is and what day it is relative to the original time. Don’t try to manually change these, since they are only for display.

3.) Sun position

Rotates the sun/moon while everything else stays the same (for example: clouds).

4.) Rotate World

Rotate everything, including clouds and sun/moon.

5.) Reduce to preview quality

0 = Final quality, 1 = preview quality.

Use this to speed up viewport, then disable it for rendering. Alternate use cases: if you don’t want clouds and high clouds in the scene, always use this option since it will speed up the sky too. Example: archviz interior. If you use Eevee for interiors, I'd recommend the Lite version even if you bought the Pro too, since it will be the fastest in viewport (especially on lower end GPU's).

II. Lighting settings

1.) Moon ON

Use this to turn on moon. 1 = ON.

2.) Sunlight strength

Default value: 5.

Higher = stronger sunlight, lower = weaker sunlight. Only in Cycles, will be updated for Eevee.

3.) Moonlight strength

Default value: 5.

Higher = stronger sunlight, lower = weaker sunlight. Only in Cycles, will be updated for Eevee.

4.) Sun disk size

Default value: 1.

Higher = bigger.

In Cycles: When the disk is smaller, the shadows become sharper. When you increase the size, the shadows become smoother. The primary function of this parameter is to change the shadows in Cycles, depending on the scenes. Realistic ones will need more sharpness, while lower poly characters look better with smooth shadows since they mask the terminator effect.

5.) Moon disk size

Default value: 1.

Higher = bigger.

In Cycles: When the disk is smaller, the shadows become sharper. When you increase the size, the shadows become smoother. The primary function of this parameter is to change the shadows in Cycles, depending on the scenes. Realistic ones will need more sharpness, while lower poly characters look better with smooth shadows since they mask the terminator effect.

6.) Light aura strength

Default value: 0.88

Use this to control the glowing aura around the sun and moon.

Higher = more visible.

7.) Light aura increase size

Increase the aura around the sun and moon. Highest value will cover the whole sky making it brighter.

8.) and 10.) Custom Sunset/Sunrise ON

Turn on to use your custom color or mix it with the original color.

9.) and 11.) Custom Sunset/Sunrise Color

Add your custom color here.

III. Mist settings

1. Mist ON

Use this to turn the mist on or off. Values between 0 and 1 will result in weaker mist.

2.) Mist strength

Default value: 1

Has a different effect compared to Mist ON, since it will keep adding more mist, making its contour stronger or weaker. Should be lowered or turned off for maximum Fog value.

3. Fog ON

Use it to add fog. Influences mist, if they add up, mist may look too strong, use Mist strength slider to fix it.

4. Mist/fog custom color ON

Turn on to use your custom color or mix it with the original color.

5. Mist/fog color

Add your custom color here.

IV. Clouds settings

1.) Amount

Change this to remove or change the amount of 3D/normal clouds.

2.) Storm/cloudy

Use this to add more clouds. This can be mixed with “Amount” to create different type of clouds. Example: Amount = 0.8 + Storm/cloudy = 0.3 will result in new type of clouds compared to using only the Amount slider.

Turn clouds Amount and Storm/cloudy to 1 and it will create a rainy, stormy feel, covering the whole sky. Add 0.8 or 0.9 fog to make it darker, more rainy. Don’t forget to lower mist for better results.

3.) Increase distance

Default value: 1.2

Use this to create smaller or bigger clouds.

Higher = smaller clouds, as our “distance” is increasing from them.

4.) Translucency

Use this for cartoony, stylized clouds or for fine tuning the cloudy/rainy clouds.

5.) Translucency flip

When it is set to 1, translucency will be flipped.

6.) Brightness, gamma, saturation

Change the color, brightness of clouds for extra fine tuning.

7.) Custom color ON

Turn on to use your custom color or mix it with the original color.

8.) Custom color

Add your custom color here.

9.) Animation

Click on the arrow to expand options.

By default the clouds have a timelapse preset, called “Clouds timelapse preset”. This is helpful if you don’t plan to create a custom animation with them. When you want to create a scene and change the cloud position/shape, just position your current frame somewhere on the timeline where you like the random cloud shape.

If you want to create a custom timelapse or manually move the clouds – or want them to stay still, then click on “Cloud timelapse preset” next to the Animation option and click “disconnect”. This will remove the preset so you can manually create an animation or let the clouds stay still.

To reconnect it, go into the shader editor (world tab) and reconnect the preset node into the purple input.

V. High Clouds settings

1.) Turn ON

0 = no high clouds, 1 = high clouds ON

Values in between: weaker, different looking high clouds.

2.) Amount

Higher = more high clouds. Default value: 1.

3.) Only horizon

Change the visibility of high clouds that are not close to the horizon. 1 = only visible on horizon.

Values in between: weaker, different looking high clouds that are not as strong as on the horizon.

4.) Distortion

Create different looking high clouds for more variety.

Default value: 0.205

5.) Custom color ON

Turn on to use your custom color or mix it with the original color.

6.) Custom Color

Add your custom color here.

7.) Animation

Click on the arrow to expand options.

By default the clouds have a timelapse preset, called “High clouds timelapse preset”. This is helpful if you don’t plan to create a custom animation with them. When you want to create a scene and change the cloud position/shape, just position your current frame somewhere on the timeline where you like the random cloud shape.

If you want to create a custom timelapse or manually move the clouds – or want them to stay still, then click on “Cloud timelapse preset” next to the Animation option and click “disconnect”. This will remove the preset so you can manually create an animation or let the high clouds stay still.

To reconnect it, go into the shader editor (world tab) and reconnect the preset node into the purple input.

VI. Sky Settings

Use the controls for a unique, personalized look. You can create darker or brighter skies.

VII. Special settings

1.) Exposure auto correct ON

When it’s set to 1, it is ON.

Default value: 1.

Makes the clouds brighter when it’s daytime to have more brightness consistency with the sunlight.

2.) Global Illumination

Default value : 0.

When it’s set to 1, it is ON.

Gives extra illumination to your Eevee scene.

Limitations:

Clouds (3D Clouds):

Since these clouds aren’t actually moving in 3D space, their movement may look a little weird when they are close to the horizon.

No cloud can cast shadow in Eevee. So you have to manually remove sunlight when you want stormy, cloudy weather. To remove sunlight, go to the Eevee sunlamp and set the color to black. You can also animate the color parameter like I did for the videos when using Eevee.