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In addition to announcing the Forecast weather service, we would like to announce the launch of the Forecast Data API, a low-drama, general-purpose weather API for developers.

The Forecast Data API grew out of the original weather data API we built for Dark Sky. The Dark Sky API was designed to be very specialized for hyperlocal forecasting, and therefore was very tightly coupled to its data sources. As we tried to expand its scope, we found that cramming other data sources into it was rather like fitting a square peg into a round hole; in the end, we decided to rebuild the API from scratch.

As I write this, we have sixteen different data sources, covering the entire globe. To give you a sense of what the quality of our data is, here is a color-coded map:

Forecast Data API Coverage Map

  • Areas in black are covered by our data sources, but suffer from a lack of quality control: we cannot reliably check the results of our predictions in these areas, and so cannot verify their accuracy. (Expect them to be more accurate the closer they are to an area of a different color.)

  • Areas in blue are covered by our data sources and are also quality controlled by checking them retroactively against weather observations. However, the data coverage is low-resolution, and so may not accurately convey local weather conditions.

  • Areas in red are covered by high-resolution, quality-controlled data sources, which should provide accurate hourly forecasts down to the local level.

  • Areas in green are covered by Dark Sky's hyperlocal prediction system, and can provide down-to-the-minute forecasts for an exact location.

Notably, we can provide hyperlocal forecasts for the United States, United Kingdom, Ireland, and small parts of Canada. Hyperlocal coverage of Canada, Australia, and more of Europe are in the works.

Additionally, with so many data sources, we can check them against each other; where they agree, we can be more confident in our predictions. If you've tried the Dark Sky API and found its accuracy lacking, we invite you to give the Forecast Data API another shot: it should be far more accurate than its predecessor.

Now that we've developed a general-purpose weather API, we're trying to compete with the other weather APIs available around the Internet. We've found those APIs to be difficult and clunky to use, so we've tried to make our API as streamlined as possible: you can sign up for a developer account without needing a credit card, and start making requests right away — you can worry about payment information when your app is ready. Additionally, we've lowered our prices so that we're competitive with the other data providers out there.

If you're interested in reading more details about working with our new API, we invite you to check out our API documentation. If you want to start playing around, you can sign up for an account on our developer portal.

Finally, stay tuned: we'll be posting here in the near future about some of the neat technical tidbits we've come across while developing this entire system; if you're a developer, we're sure you'll find it interesting! You can keep on top of what we're up to through this blog or through Twitter.