Technically most of the weather data is derived(within the United States) from the National Weather Service, all of this data is a matter of public domain under federal law(so it’s being subsidized by taxpayers). What companies like the weather channel or accuweather can do is increase the accuracy by adding more stations and providing more compute power to run more powerful simulations(something the NWS can’t do because of budgetary constraints) or what an app like Carrot can do is allow you to add your own weather station and interpret the data to give predictions.