Abstract: In the 2015 Advances in Real-Time Rendering Course, we presented a prototype solution for real-time volumetric cloudscapes which produced a variety of cloud types in various lighting conditions and rendered in under 2 milliseconds on the PlayStation 4. However, many practical challenges remained in the way of it becoming a successful production tool for use in our game Horizon Zero Dawn: authoring cloudscapes on a regional scale, animation and transitions, integration into our atmospheric system, further optimization to pay for these new features, and the task of creating a language and long term plan for what we want to achieve in the context of our game engine, Decima. Nubis is our solution to these challenges. This talk will explain how and why the Nubis system works and highlight some advances beyond the prototype that we presented in 2015, including changes to the lighting model. In addition, we will go a bit more in-depth for several topics that have garnered interest in the development community, namely Perlin-Worley noise generation and our weather simulation. Finally, we will offer a quick look ahead to where we are going next with Nubis.