GrayCloud vs Dark Sky

What Apple kept from Dark Sky, what got cut, and how GrayCloud restores the parts you actually used.

The short version

Dark Sky is gone. The iOS app was wound down by early 2023 and the developer API followed at the end of March 2023. Apple Weather inherited the minute-by-minute precipitation block, but the rest of Dark Sky - the open API, the geeky model commentary, the indie-feeling UI, the embeddable widgets - did not survive the transition.

GrayCloud is built to be the spiritual successor. Same minute-by-minute precipitation idea, run at higher radar resolution through a proprietary nowcasting engine. Same Dark Sky-shaped JSON API on the backend, ready for the day developers can use it. Same single-page weather-nerd UI, on iPhone, Apple Watch, Mac, and the web.

Feature-by-feature

Minute-by-minute precipitation

The single feature most people remember Dark Sky for. Dark Sky generated its 60-minute precipitation forecast by running optical-flow nowcasting on radar data - extrapolating the motion of the rain you can already see to project where it will be in the next hour.

GrayCloud uses the same idea against a sharper input. Dark Sky's radar source was a commercially-licensed mosaic; GrayCloud runs a proprietary nowcasting engine on a national radar feed updated every two minutes at kilometer-level resolution. The nowcast lives in the same place in the UI: a strip across the page that turns from light to medium to heavy as the rain reaches you.

Accuracy transparency

Dark Sky never published a forecast accuracy number you could audit. Apple Weather doesn't either. GrayCloud does - we score every forecast nightly against observed truth and publish the rolling error on a public scoreboard. The forecast engine itself is proprietary; the accountability is not.

If a forecast is suspicious - say a thunderstorm appears for hour 36 but the next-hour radar is clear - you can check the scoreboard's recent calibration for your region and decide whether to trust it.

The API question

If you are reading this page because your Dark Sky API integration broke in March 2023, here is the short version. GrayCloud's forecast backend already speaks the Dark Sky JSON dialect internally; the public, paid API tier is on the roadmap. When it ships, migrating from Dark Sky will be a hostname swap, not a parser rewrite. More on the GrayCloud architecture →

Privacy

Dark Sky, in its final years, was an Apple-owned app subject to Apple's analytics and advertising frameworks. GrayCloud has no user accounts, no third-party analytics, no advertising SDKs, no data sold or shared, and no cookies on the web app. iCloud Key-Value Store is used for cross-device sync between your own iPhone and Mac - your data never touches a GrayCloud server.

What Dark Sky did that GrayCloud doesn't (yet)

• Minute-by-minute outside the US. Dark Sky covered the UK and Ireland with minutely precipitation. GrayCloud's minute-by-minute is US only until ICON-EU and HRDPS coverage lands.

Try GrayCloud

Or open the web app - type an address at /forecast for a forecast right now, with nothing to install.

See also: the full Dark Sky alternative overview · vs Apple Weather.