We have made a number of updates to hourly forecasts in the Dark Sky API:

  1. We have developed a brand new forecasting model. This model is the result of over a year of research and development, and brings a number of major improvements over our previous model:

    1. Our global (worst-case) resolution has been improved from ~40km resolution to ~20km resolution.

    2. We now explicitly account for microclimate effects in our air temperature forecasts. This gives our temperature forecasts a virtual resolution of <1km.

    3. We no longer ingest the RAP and RTMA models. Instead, we now ingest the HRRR model (which is RAP’s successor).

    4. We now perform global accuracy assessments for each source model, and use this information in a statistically rigorous way to inform how we remove bias from and combine the models into our final results.

    Altogether, this means that our new model is much more accurate than our previous model was. Additionally, it is much easier than before to incorporate new data sources, and we hope that this will speed international expansion, though we do not yet have any announcements to make on that front yet.

  2. API responses now include wind gust speed and UV index.

  3. The API now computes daily precipitation probability using a completely new approach, which is more accurate than our previous method.

  4. We have fixed a number of bugs, particularly in cases where we report unusual current conditions.

  5. We have made a lot of optimizations and performance improvements to how we consume our forecasting model, which should reduce the latency involved in receiving weather model updates and should reduce API’s average response time significantly.

Details may be found in our documentation.

You may have noticed that over the last couple months (1, 2), we’ve been rolling out big behind-the-scenes updates to each of the systems underlying the Dark Sky API. This release completes that process, and paves the way for a major update to the API coming later in the year. This update will take full advantage of these updates to provide a lot of interesting and powerful new features, and we’re very excited to begin showing them off! Stay tuned for updates, and as always, thanks very much for your continued support.