Update to Google’s AI weather model improves forecast accuracy

Ars Technica Models

Summary

Google's AI weather model WeatherNext 3 has been updated to use more raw satellite data and incorporate physical information, improving forecast accuracy by up to 30% for surface temperature, and is now the source for forecasts in Google services.

<p>Google is one of the major players in AI (meaning machine learning) weather forecast model space. The models it and others generate have their <a href="https://arstechnica.com/science/2026/06/the-weather-and-climate-science-ai-revolution-isnt-revolutionary/">strengths and weaknesses</a>, but the main advantage is that they can have forecast performance similar to traditional models while requiring far less computing horsepower to run. That means they can be run more frequently.</p> <p>Google recently <a href="https://blog.google/innovation-and-ai/models-and-research/google-deepmind/introducing-weathernext-3/">released version 3</a> of its WeatherNext model, with the biggest change being that it now ingests some satellite weather data, shortening the lag time between current weather conditions and generating a new forecast. The update is detailed in a <a href="https://arxiv.org/abs/2609.03582">white paper</a>.</p> <h2>Reanalysis</h2> <p>Many weather models make use of what’s called a “reanalysis,” which is a sort of model of its own. Reanalyses take in all kinds of weather data and combine them into a single, consistent global snapshot of the atmosphere. That requires that they provide estimates for conditions over locations without real-world measurements, because weather forecast models need to work with a global picture.</p><p><a href="https://arstechnica.com/science/2026/09/googles-ai-weather-model-now-uses-more-raw-satellite-data/">Read full article</a></p> <p><a href="https://arstechnica.com/science/2026/09/googles-ai-weather-model-now-uses-more-raw-satellite-data/#comments">Comments</a></p>
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# Update to Google’s AI weather model improves forecast accuracy Source: [https://arstechnica.com/science/2026/09/googles-ai-weather-model-now-uses-more-raw-satellite-data/](https://arstechnica.com/science/2026/09/googles-ai-weather-model-now-uses-more-raw-satellite-data/) Unlike traditional models that use physical properties in a location to simulate physical processes, machine\-learning models are largely black boxes that train on past patterns and spit out predictions of future patterns\. But WeatherNext 3 is adding a tiny bit of physical information to calculate surface temperature and dew point at any specific location you want to pull up\. It checks whether that point is land or ocean and uses its surface elevation\. By training on past weather station data tagged with that information, the team says they get better forecast predictions\. ## Some oddities The white paper shows some results to document forecast performance improvements over WeatherNext 2, as well as the European Centre for Medium\-Range Weather Forecasts \(ECMWF\) AI model\. They note a roughly 5 percent improvement in upper atmosphere condition accuracy over their previous model, for example, which they say equates to about six more hours of accurate forecast lead time\. And their change to calculating surface temperature for a specific location improved accuracy by up to 30 percent\. They’re generally beating the ECWMF model on these metrics as well\. There is one curious exception that the paper doesn’t even guess at the cause of\. For a number of variables, their comparison to the initial six\-hours\-ahead forecast from the other models shows WeatherNext 3 doing*worse*before pulling ahead for the rest of a 15\-day forecast\. Larger\-scale patterns are also not without some weirdness\. You can see the shape of the model’s grid in some predictions, like the map of precipitation showing some distinctly hexagonal blobs\. Their method of generating multiple surface temperature forecasts to represent the range of possible outcomes also has a habit of producing snapshots where the*global average*temperature is higher or lower\. Normally, you would want to see the average be consistent, with local\-scale variability that averages out across the globe\. Overall, the team says their new model “represents a major step forward for AI\-based weather predictions by going beyond relying purely on analysis and utilizing information\-dense, low\-latency observation data\.” WeatherNext 3 is now the source of forecast information across Google services, including Search, Gemini, and Maps\.

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WeatherNext 3 is an advanced AI weather forecasting model from Google that incorporates real-time satellite data, hourly refreshes, and precise precipitation forecasting, now integrated into Google services like Search, Gemini, Maps, and Cloud.