Microsoft Aurora

Aurora is Microsoft Research's foundation model for atmospheric prediction, first described in a May 2024 preprint and published in Nature in May 2025. Rather than training one model per forecasting task, the team pretrained a single encoder-based model on over one million hours of atmospheric data — satellites, radar, weather stations, and simulations, described as the largest such collection ever assembled — then fine-tuned it for medium-range weather, air quality, ocean waves, and tropical cyclones.

Fine-tuned Aurora beat existing numerical and AI systems on about 91% of medium-range forecasting targets at 0.25-degree resolution, and a specialized version already powers hourly forecasts in MSN Weather. Notably, Microsoft released both code and weights openly (MIT-licensed checkpoints on Hugging Face, e.g. aurora-0.25-pretrained), making it one of the rare frontier-class scientific models the community can actually run and build on.