Weather · head-to-head
Hong Kong Observatory vs RainViewer
The Hong Kong Observatory's Open Data API exposes roughly 50 machine-readable datasets covering real-time weather observations, 9-day forecasts, lightning counts, tropical cyclone tracking, tidal predictions, UV index and radiation levels, plus historical rainfall and sunshine records, for Hong Kong and nearby waters. It is a free, keyless service built for machine-to-machine consumption, mirrored on the government's data.gov.hk portal alongside the Observatory's own documented endpoint.
RainViewer aggregates and re-tiles third-party radar imagery from over 1,200 radar stations across 150+ countries, refreshed every 5 minutes, and exposes it as XYZ PNG tile pyramids plus a JSON timeline endpoint listing available past and short-term nowcast frames. Coverage isn't guaranteed to be permanent since individual source radar owners can request their feed be pulled, and the service is explicitly licensed for personal, educational, and small-scale community projects only.
| Hong Kong Observatory | RainViewer | |
|---|---|---|
| Authentication | None | None |
| Pricing | free | free |
| Formats | JSON, XML, CSV | JSON, PNG |
| CORS | yes | yes |
| HTTPS | Yes | Yes |
Hong Kong Observatory supports 3 response formats, while RainViewer offers fewer — pick Hong Kong Observatory for more integration flexibility.