Strange Weather refers to multiple myths in the Grand Theft Auto series.
Red Fog and Hellish Skies
Red Fog is a myth in Grand Theft Auto: San Andreas. It tells about a mysterious red fog, which can be seen in all areas of San Andreas in stormy weather at night. The Blood Red Fog myth is a well-known phenomenon in the game, but it is yet to be proven (as a myth). This fog can be seen everywhere around the state of San Andreas.
The Hellish Skies myth is a proven phenomenon within the game. This glitch can be replicated, but it is rather difficult. If the player is in the Las Venturas landmass during a sandstorm at sunset, and then the player flies very quickly to San Fierro or Flint County, the horizon will turn a foggy, dark red color. The skies will continue to exhibit this strange hue until nighttime, and the sky will turn black as usual. This phenomenon is most likely a weather glitch.
The Blood Red Fog only occurs on the PC version of San Andreas, because the PC version has an error in the timecyc.dat file which causes the game to set incorrect sky colours and ambient lighting at 8 PM during rainy weather in the countryside. The weather effects are interpolated with the previous (7 PM) and next (10 PM) timecyc.dat settings, so the effect can be seen any time between 7 PM and 10 PM, particularly between 7:30 PM and 9 PM. This is also the reason why textures are very bright during this period, almost as if it were the middle of the day.
The Neon Green Fog is a very rare occurrence which usually only happens around The Bayside Chemical Manufacturing Plant, or around country-side in general. There are very few photos and videos which show this strange phenomenon occurring. The fog is rumored to be a chemical residual of the Bayside Chemical Plant. Several green clouds can also be seen at night in GTA Vice City, although their purpose in the game is still unknown. They are often linked to the Bermuda Triangle and Hurricane myth. The cloud may very well be the shadow of the sea color at night.
A neon green fog can be observed in GTA SA, during the mission First Base. A suicidal pedestrian can also be perceived in the fog, by the river. Dense/Giant fogs were also a subject of controversy in GTA III.
Glowing Water is another weather symptom, which involves the water glowing white in San Fierro or the countryside. It only occurs during the sunrise hours between 5 AM and 7 AM, and it does not occur in Bone County, Las Venturas or Los Santos. There has been at least one video and several photos online showing this strange phenomenon.
This phenomenon is caused by some of the San Fierro and countryside weather types in the timecyc.dat file having a parameter known as "LightOnGround" enabled with a very high value at 6 AM; it is normally not meant to be used as it does not function properly in San Andreas, but was used in previous GTA games to gradually lighten up the ground during sunrise. Since some of the timecyc.dat code for the San Fierro and countryside weather was taken directly from previous games, it results in a bright white glow above any body of water during the early morning.
The Golden Skies Myth in GTA San Andreas is probably one of the rarest and least discussed myths in the game, only having been discussed on the closed website for video game myth hunter, called VGPI. This myth, and every reference to it got removed when the founder Cf0x3o6 shut down the website. The myth had only one small thread, and only a few people ever discussed on it, or even saw it. The myth itself said about the skies over Los Santos, Glowing Gold. This is supposed to be one of the rarest occurrences in the game, and is highly debated. The Gold Skies myth is very unlikely. However, one person has sighted the golden skies and managed to take a picture.
This is the last 'Strange Weather Myth,' which also had only one small thread on the VGPI website. The myth said about rainbow skies and fog, and has no references at all, only possibly one. The Rainbow Skies Myth is also possible. On another note, it is possible to see a rainbow in San Andreas, but it will be a single vertical band with 6 colors, as opposed to the more traditional arch 7 color rainbow we see in the real world. The player is most likely to spot a rainbow in Queens, San Fierro, as the city district has a very obvious LGBT theme. Similar to GTA San Andreas, these rainbows can also be observed in GTA Vice City.