Here's how Google Home gets the data for its weather forecast

For Google Home, WeatherNext 2 provides hourly and daily forecasts, along with MetNet and other models, according to Google.
IEEE

Day-Ahead Weather and Load Forecast using Machine Learning: Comparative Analysis

Abstract: Global energy use is shifting towards integrating more renewable energy sources (RESs) in smart grids, especially solar systems and wind turbine, whose performances are quite affected by the ...