OpenWeatherMap APIs Overview

Learn more about the OpenWeatherMap APIs, their weather prediction model, and their performance metrics.

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Accuracy and quality of weather data

OpenWeather ensures the delivery of accurate data to its users by using its tools to observe accuracy and quality metrics. Let’s look at the weather prediction models and the different metrics employed to evaluate the accuracy of the generated data.

Numerical weather prediction model

OpenWeatherMap APIs provide weather data using its numerical weather prediction (NWP) model. This model gathers data from a number of data sources listed below:

  • Global NWP models: NOAA GFS 0.25 and 0.5 grid sizes, NOAA CFS, ECMWF ERA
  • Weather stations: METAR stations, users’ stations, companies’ stations
  • Weather radar data
  • Satellite data

OpenWeather uses its own array of algorithms to process the data gathered from these sources. This processing is done in real-time to improve the accuracy and quality of metrics. Moreover, it provides the latest current weather data and weather forecasts.

Metrics

OpenWeather considers several reliable sources to compare forecasts, including multiple weather stations run by meteorological agencies. Moreover, weather radar sources are used for comparing precipitation forecasts.

The quality evaluation metrics can be divided into the following three groups:

  1. Common scores that show the accuracy of forecasts, intended for forecast users.
  2. Metrics used to compare various raw data sources, and algorithms used to choose between them after processing.
  3. Diagnostic metrics that are used to improve forecasts by limiting certain types of errors in them.

These metrics are used to evaluate the quality of weather forecasts for common and special purposes.

Cities

A total of 371 cities are used to evaluate weather data. These include national capitals along with many other major cities across the world.

Conclusion

OpenWeather’s numerical weather prediction model provides high accuracy readings between 90% and 100%, with an inaccuracy of only about 1%. NWP’s data sources include 82,000 weather stations across the globe, national meteorological agencies (NOAA, Environment Canada, Met Office, and so on), radars, and weather satellites.