Open-Meteo
Open-Meteo is a fully free and open-source weather API that provides high-resolution global weather forecasts, historical weather data, and climate projections without requiring any API key for non-commercial use. Built on top of state-of-the-art numerical weather prediction (NWP) models from ECMWF, GFS, Meteo France, DWD, and other meteorological agencies, Open-Meteo delivers hourly and daily weather variables across the globe with up to 16-day forecast horizons and access to decades of historical weather records. For Nigerian developers building weather-dependent applications who want a zero-cost starting point, Open-Meteo is one of the most capable free weather APIs available.
Forecast data from Open-Meteo covers a wide range of weather variables: temperature at 2 meters, apparent temperature (feels like), precipitation, rain, showers, snowfall (unlikely in Nigeria but globally relevant), cloud cover, wind speed and direction at multiple heights, wind gusts, surface pressure, relative humidity, dew point, visibility, shortwave solar radiation, and cape (Convective Available Potential Energy for thunderstorm prediction). For Nigerian agricultural apps, the combination of precipitation forecasts and solar radiation data is particularly valuable for irrigation scheduling and solar energy production forecasting.
The API returns data in hourly or daily resolution, selectable per request. Hourly data enables fine-grained analysis of weather through the day — important for Nigerian logistics operations planning around Lagos or Abuja rush-hour weather, or for event managers checking window-by-window rain probabilities for an outdoor concert. Daily data provides simplified summaries including max/min temperature, precipitation sum, sunrise/sunset times, and UV index maximum — ideal for Nigerian travel apps showing week-ahead weather summaries.
Historical weather data through Open-Meteo is available from 1940 to the present via the Historical Weather API endpoint, sourced from the ERA5 reanalysis dataset by ECMWF. Nigerian climate researchers, agricultural historians, and developers building data analytics tools for climate trend analysis can access decade-long weather records for any location in Nigeria including remote northern and southern regions without subscription costs. This historical depth rivals expensive commercial weather data providers.
Marine forecasting is supported through a separate marine endpoint returning wave height, wave direction, wave period, swell height, and ocean surface temperature — relevant for Nigerian fishing communities, port operators in Lagos and Apapa, and oil and gas companies operating in the Gulf of Guinea. The marine data combined with standard atmospheric forecasts gives a complete picture of weather-related conditions for offshore and coastal Nigerian operations.
Air quality forecasting from Open-Meteo includes PM2.5, PM10, ozone, nitrogen dioxide, sulphur dioxide, carbon monoxide concentrations, UV index, and European and US Air Quality Index calculations. Nigerian urban health apps monitoring air quality in Lagos (which has significant vehicle and industrial air pollution) can use the air quality forecast to send pollution warnings and health advisories to users.
Climate projections through the Open-Meteo Climate API provide future temperature and precipitation projections from CMIP6 climate models, allowing comparison of projected future climate against the historical baseline. Nigerian policy researchers and environmental NGOs can use these projections to model climate change impacts on Nigerian agriculture, water resources, and urban heat islands.
Open-Meteo is free for non-commercial use with no API key required — just call the endpoint with latitude, longitude, and the desired weather variables. Commercial use requires a subscription which remains affordable at under $50/month for most volumes. The API is highly reliable, well-documented, and used by thousands of developers worldwide, making it a strong foundation for any Nigerian weather-aware application.