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  3. Details Regarding Forecast Updates

What happens before a forecast is available in the API?

An explanation of the required processes before a weather forecast becomes available in the Spire Weather API.

All global forecast models require some amount of time before new forecasts are made available.

The reason for this is as follows:

  1. Forecasts are based on observational data collected during a window of time, on the order of hours.
  2. After this full window of time has elapsed, there is a shorter "waiting period" to allow those observations to arrive at the location where they will be combined with Spire's global model.
  3. When this data collection phase concludes, the computation phase begins and the data assimilation system starts its work of data quality assurance and analysis. This process also takes some time.
  4. Once these actions are completed, the actual forecast calculations begin.

    Unlike most other weather data providers, Spire owns and operates each individual component of the value chain - from our satellites in orbit to our end-user forecast products. Although it is not critical to understand all of this information to use our APIs, Spire takes great pride in delivering unique value to each process along the way.

    Spire is always actively exploring methods to optimize and improve our processes, but at least in the near term some degree of latency is to be expected. This is in line with other top providers such as NOAA and ECMWF.

    To summarize: some time is needed for the movement of the data and the full forecast calculation.

    Please note that users also have access to previously published forecasts while the latest data is being processed.

    For more information on how to handle actively updating forecasts, please see here.