Aurora 1.5: Extending open foundation models for weather and Earth-system applications

Aurora 1.5: Extending open foundation models for weather and Earth-system applications - Microsoft Research

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At a glance

Aurora 1.5 is a major extension of Microsoft’s Aurora Earth System foundation model that adds 22 more weather variables relevant to energy, agriculture, transport, and climate risk, along with hourly temporal resolution and probabilistic ensemble forecasting.

Released as open source on GitHub with model checkpoints on Hugging Face, Aurora 1.5 enables researchers and developers to use, evaluate, and build on the model.

Aurora 1.5 connects open research to Microsoft Weather services, linking the model with data, infrastructure, managed access, and operational use for weather and Earth-system applications.

Aurora 1.5 is a major update to the open Aurora Earth-system foundation model, adding 22 new weather variables for a broader view of atmospheric conditions, hourly forecasts, and probabilistic ensemble forecasting. Developed by Microsoft Weather as an extension of the original model from Microsoft Research AI for Science, Aurora 1.5 shows how frontier research can move into broader use: open for researchers and developers to evaluate and extend, and designed to support customers where additional data, infrastructure, and operational assurance is needed. As climate and weather-related risks continue to affect communities, infrastructure, and economies worldwide, advances in Earth-system forecasting can help improve preparedness and decision-making.

What is Aurora?

Aurora is a foundation model for the Earth system developed by Microsoft Research AI for Science, first introduced in 2024 and published in Nature (opens in new tab) in 2025. It showed that a single model could be adapted to medium-range weather, ocean waves, atmospheric chemistry, and emerging climate applications, including high-resolution weather forecasting through fine-tuning. Its growing use has reinforced the value of an open, collaborative model that is easier to adapt, evaluate, and put to use.

This next phase of Aurora (opens in new tab) builds on that foundation by making the model openly available for the global community to adapt, extend, and build on.

What is new in Aurora 1.5?

Aurora 1.5 advances the broader effort to make open weather foundation models practical and scalable for organizations that rely on atmospheric and Earth-system intelligence. Alongside new variables and higher temporal resolution, Aurora 1.5 adds one of the most requested capabilities from users: ensemble forecasting. Because forecasts are sensitive to initial conditions and model uncertainty, ensembles run multiple simulations to show the range and likelihood of possible outcomes. Aurora 1.5 builds on Microsoft Research’s scientific foundation with new product engineering, cloud infrastructure, managed access, and decision-support capabilities. Together, these advances make Aurora 1.5 a valuable enterprise-grade weather solution for organizations.

Figure 1: Illustration of the capabilities of Aurora 1.5 ensemble for predicting new impactful parameters such as total cloud cover and solar radiation. Ensemble mean and standard deviation are shown .

The breadth update adds 22 new variables to Aurora’s original 4, including representative surface, pressure-level, wind, temperature, humidity, precipitation, and radiation fields. That broader coverage makes the model more relevant for sectors that depend on integrated Earth-system signals, from energy and agriculture to transport and resilience planning.

The update to hourly temporal resolution enables fine-grained detail for precision operational guidance, such as the onset of precipitation, trade decisions, or a landfalling tropical cyclone.

“Aurora 1.5 is a meaningful step toward making weather foundation models more open, useful, and practical. By releasing the model openly, we give researchers, developers, and organizations a clearer path to evaluate it, adapt it, and understand where it can help. Microsoft Weather’s role is to connect that open research foundation with the data, infrastructure, and applied workflows required by enterprises to use weather intelligence responsibly and with confidence.”

Sridhar Iyer, Corporate Vice President, Microsoft AI

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Ensemble Forecasting in Aurora 1.5 Unlocks More Confident Decisions in the Face of Weather Uncertainty

The ensemble version of Aurora 1.5 introduces stochastic perturbations to represent model uncertainty, allowing the generation of multiple forecast members to estimate the spread of possible futures. For a multitude of applications including power systems, transport, agriculture, extreme-weather planning, and climate...