Although it may not seem like it, weather forecasts are better now than they’ve ever been. “Over the past 40 years, we’ve been adding an additional day of skill each decade,” says David Novak, Director of the Weather Prediction Center at the U.S National Weather Service. In other words, forecasts made today about the weather five days from now are roughly as accurate as were weather forecasts made four days out in 2013.
Government agencies, such as the U.S. National Weather Service and the U.K. Meteorological Office, run vast meteorological models on supercomputers. Improvements in forecast accuracy are mainly due to these models becoming larger, allowing them to use new sources of data and model the climate in greater detail. Governments provide the forecasts from these models to the public and to commercial weather forecast providers for free.
Despite the general improvement, there are large differences in accuracy between different weather apps, and the app that provides the most accurate forecasts can vary by location.
There are around two dozen forecast providers in the U.S, says Eric Floehr, founder and CEO of weather forecast accuracy monitoring company ForecastWatch. Each of these providers starts with the forecasts made by government models, then adds sources of data, such as information from proprietary weather stations, and develops techniques to improve their accuracy. This secret sauce accounts for the variation in accuracy by forecaster. Forecast providers sell their forecasts to app developers or build their own apps. They also sell their forecasts to businesses, such as airlines, that are willing to pay for the best weather forecasts possible.
