Aurora 1.5: Extending open foundation models for weather and Earth-system applications
TL;DR
Microsoft announced Aurora 1.5 on July 9, 2026, adding 22 weather variables, hourly forecasts, and ensemble forecasting to its open Earth-system foundation model. The model is open source on GitHub, with checkpoints on Hugging Face. Researchers and developers can evaluate it, adapt it, and plug it into weather or climate workflows. Microsoft claims strong benchmark results: Aurora 1.5 beats ECMWF ENS on 88.9 percent of evaluated targets and reduced track errors in tests on Hurricane Helene 2024.
Nauti's Take
Aurora 1.5 is the kind of AI update where the dry engineering details matter more than the grand research framing. Hourly resolution, more variables, and probabilistic forecasts are the parts that can turn an impressive model into a usable decision system.
The catch: Microsoft is telling a research story, an open-source story, and an enterprise sales story at the same time. Anyone adopting it should test the model against local data, current weather providers, and their own tolerance for forecast errors.
Briefingshow
Aurora 1.5 moves foundation-model thinking closer to weather, energy, agriculture, and risk planning. The practical shift is not just better averages, but uncertainty: ensembles show several plausible futures instead of one polished forecast. That matters more for power grids, transport, and extreme-weather planning than a clean demo score.
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