Aemet vs IPMA

AEMET OpenData is the official REST API of Spain's national meteorological agency, publishing forecasts, observations, climatology, and warnings ("avisos") restricted to Spanish territory. Requests return a metadata JSON envelope containing a signed URL that must be fetched separately to retrieve the actual payload (JSON, XML, or CSV depending on endpoint), and the service is documented via an interactive Swagger UI and machine-readable OpenAPI spec.

IPMA's open-data service is a plain directory of continuously-refreshed static JSON files, not just a single forecast endpoint: it covers daily/hourly weather forecasts, real-time station observations, sea-area and district warnings for mainland Portugal, the Azores and Madeira, plus separate seismic and biology (pollen) datasets from the same institute. No registration is required, though IPMA asks heavy users to email its webmaster for usage statistics.