GTA 3's dynamic weather effects explained by ex-Rockstar dev

GTA 3's launch in 2001 was a significant turning point in the open-world gaming genre. While the Rockstar Games title is quite fascinating as a finished product considering the technological limitations of its time, certain aspects of its development are just as intriguing. Former Technical Director at Rockstar North, Obbe Vermeij, recently divulged how GTA 3's dynamic weather effects were implemented.

For those unaware, the game features four types of weather effects in total. As per the ex-Rockstar dev, they were initially intended to transition randomly based on a percentage system. However, due to tester bug reports, a table-based system was put in place instead.

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Ex-Rockstar Technical Director Obbe Vermeij explains how GTA 3's dynamic weather effects work

Sunny, overcast, rain, and fog are the four types of weather that one can witness in GTA 3's gameplay. Obbe Vermeij initially used a "random chance" system to transition between these weather effects. Here's what he stated:

"Initially, I used a random chance for each transition between weather types. Ie 40% for Sunny->Sunny, 20% for Sunny->Cloudy etc."

Unfortunately, the unpredictability of this system resulted in a stream of bugs that prevented the weather from being changed for many in-game days. In response, Vermeij switched to a table-based system, wherein each weather effect would only repeat after 64 in-game hours.

"In other words; if it rains now, it will rain again 64 in-game hours later."

To put things into perspective, according to the popular website - GTA Wiki, one in-game day lasts 24 real-life minutes in Grand Theft Auto's 3D Universe, which consists of Grand Theft Auto 3, Vice City, and San Andreas.

The ex-Rockstar dev has, notably, also highlighted in the same X post that titles after GTA 3 featured additional weather effects. He used the example of how GTA Vice City features a clear sky, which is essentially sunny but without any clouds.

An example of a clear sky in GTA Vice City (Image via Rockstar Games)

Another interesting thing mentioned by Obbe Vermeij is that level designers had the freedom to override weather using script commands for specific GTA 3 missions. The example used by him here was certain races not taking place in rain as that weather type affected a car's grip.

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Obbe Vermeij left Rockstar in 2009 after having spent over a decade at the company. It goes without saying that video game development has progressed greatly since the days of GTA 3. However, it still serves as one of the best examples to understand just how the Grand Theft Auto series itself has evolved.

The series' next installment, GTA 6, will be out in Fall 2025 and looks like it could revolutionize the gaming industry just like Grand Theft Auto 3 did all those years ago. Until then, players can keep themselves entertained with the upcoming GTA Online Bottom Dollar Bounties DLC.