One of the biggest cop-outs in game design today is clouds. They’re tricksy little things, difficult to make look realistic because real clouds often have a dramatic, otherworldly appearance that looks fake already.

Think about your favourite games. How many of them are set indoors, or at night, or underground? How many have a perspective that looks down from above, meaning that there’s no need to render anything above ground level? Even those that do depict a daytime scene often just stick a sun in the heavens and leave it at that.

But done right, clouds can add tremendous majesty, presence and realism to a scene. Let’s take a look at a few of the best games of the last decade or so to see exactly how the developers have used clouds and what effect they give to the mood of a screenshot.

Starting with Monkey Island 3. Being a point-and-click adventure game, the backdrops are all hand-drawn and stylized. Clouds feature in almost every scene, from the opening vista with Guybrush in a dodgem car and a huge moon, to the duel on top of the hill overlooking the town and LeChuck’s ship sailing off into the sunset.

Each lends a slightly eerie but fantastic quality to the skies, matching up closely with the tone of the game itself. Despite tropical clouds having almost nothing in common with those shown in the Monkey Island games, they still have an evocative quality that suits the game perfectly.

Next up, is GTA IV. Instead of an artistic approach, GTA IV goes for a much more photorealistic style for the city and everything in it. As a result, the clouds are typical stratocumulus that New York might see at any time of the year. They look good, though – blending in without being too flashy.

You can see exactly what an effect they have by comparing that last image to a shot of GTA: Vice City’s sky. Instead of definable shapes, there’s just a vague whiteness which isn’t remotely convincing and doesn’t match up with the much more defined edges to clouds that you tend to get in the tropics (because they’re more likely to be made of water, not ice).

Another game that goes for a similarly photorealistic approach is Half-Life 2. But City 17’s clouds feel a lot more ominous than GTA’s, hanging low overhead and letting the sun poke in from the horizon, casting long shadows across the ground. This gives an oppressive feel to the game, suiting Valve’s Orwellian city-state excellently and keeping you on your guard.

Imagine if the same scene had blazing sunshine and gave the impression of a warm, sunny day. You’d end up thinking: “Maybe that Doctor Breen isn’t so bad after all. Do we really need to be taking down the citadel?”

Perhaps the ultimate in photorealism is the clouds in Microsoft Flight Simulator, which billow and float in an agreeably physics-generated sorta way. Thanks to the perspectives required, though, Flight Sim’s clouds have to look good – players will be viewing them from any and every angle, and so they have to be convincing to maintain the illusion that you’re really a 747 pilot, flying the red-eye.

Flight Sim is one of the few games that gets that depending on the position of the sun, clouds can be either lighter or darker than the sky around them. The refraction of light around the water droplets in a cloud means that they can dim a bright scene, but they can also light up the dark, especially at dusk. Microsoft’s cloud engineers seem to have done an exceptionally good job on them.

There’s a tonne of other examples I could look at, but let’s leave things there for now. What are some of your favourite clouds in videogames, realistic or not? Take a screenshot and post it in the comments.