Open-Meteo
From AltData.wiki, The Alternative Data Encyclopedia
Open-Meteo is an open-source weather-data service that provides forecast, historical, air-quality, marine, climate, and related information through web APIs. Its principal forecast interface combines numerical weather-prediction output from multiple national and regional providers behind a common request and response format.[1][2]
The public service permits limited non-commercial use without an API key, while subscriptions provide commercial-use rights and reserved capacity.[1][3] The server code is published under the GNU Affero General Public License, and the website states that API data are distributed under the Creative Commons Attribution 4.0 license.[1]
What It Does
Open-Meteo accepts geographic coordinates and requested variables, then returns current conditions or time series in formats intended for software use.[1][2] The forecast API supports hourly, daily, and selected 15-minute variables, including temperature, precipitation, humidity, pressure, cloud cover, wind, solar radiation, soil conditions, and derived measures.[2] It can also return CSV and spreadsheet output in addition to JSON.[1][2]
The service is an aggregation and delivery layer, not a national observing agency. Its inputs include models produced by organizations such as the European Centre for Medium-Range Weather Forecasts, Germany's DWD, the United States' NOAA, Meteo-France, the UK Met Office, and other meteorological services.[1][2]
Data And Methodology
Open-Meteo documents a default best-match option that selects an applicable high-resolution model for the requested location. It combines successive model runs into a continuous series and normalizes output to a common temporal structure.[1][2] A user may instead select individual models for comparison or model-specific processing.[2]
Forecast values are model outputs rather than direct station observations. Resolution, update frequency, forecast horizon, and available variables differ by provider and region.[2] The documentation also notes that some sub-hourly values outside covered regions are interpolated from hourly data.[2] These distinctions matter when the API is used for verification, operational decisions, or machine-learning training.
Products
Alongside the main forecast endpoint, Open-Meteo lists APIs for historical weather, archived forecasts, individual and previous model runs, ensembles, seasonal forecasts, climate projections, marine conditions, air quality, satellite radiation, geocoding, elevation, and floods.[2] Its historical layers serve different analytical purposes: reanalysis supplies long, spatially complete series, while archived forecasts preserve values as they were issued and can reduce look-ahead bias in retrospective work.[1]
The public homepage describes the interface as ordinary HTTP GET requests with query parameters and consistent variable names across live and historical products.[1] Self-hosting is possible from the published server source, but doing so requires the operator to obtain, process, and serve the upstream datasets and to comply with applicable licenses.[1]
Delivery And Pricing
The free endpoint requires neither registration nor an API key and is subject to published minute, hour, day, and month limits.[1][3] Open-Meteo states that this endpoint is for non-commercial use and has no uptime guarantee.[3] Paid plans use a customer endpoint and API key, include a commercial-use license, and run on reserved capacity with a stated uptime target.[3]
Plans are differentiated by monthly call budgets, access to selected historical and specialist APIs, support, and custom arrangements.[3] Because allowances and prices can change, applications should read the current pricing and license pages rather than treat a quoted plan figure as permanent. Attribution remains required under the stated data license.[3]
Landscape And Verification
Open-Meteo occupies a layer between primary meteorological model producers and applications that need a unified interface. Its value lies in normalization and convenient delivery; authority for a particular forecast model remains with the originating weather organization.[1][2] The Internet Archive independently records an archived copy of the service's public website, providing a dated external record of its presentation and availability.[4] No independent audit of forecast accuracy or service reliability was located in the reviewed sources, so those qualities should not be inferred from the breadth of documented coverage.