Who are the best providers of weather data APIs for predicting renewable energy production?

If your goal is forecasting actual renewable generation rather than simply retrieving weather forecasts, I’d focus on providers with solar irradiance, hub-height wind, high temporal/spatial resolution, historical/reforecast data, and ideally power-forecast models.

My shortlist

1. Meteomatics — strongest all-around option

This is probably the first provider I'd evaluate for a commercial solar + wind forecasting platform.

Meteomatics combines 100+ weather sources/models, historical data going back to 1940, high-resolution downscaling, ensembles, and energy-specific variables. More importantly, it offers actual solar and wind generation forecasts, not just the meteorological inputs needed to build one.www.meteomatics.com+1

For solar, for example, its system can incorporate plant orientation, tilt, capacity and tracking configuration and deliver forecasts at up to 15-minute resolution, including plant/portfolio output.www.meteomatics.com+1

Meteomatics Energy Forecasting

Particularly interesting if: you're doing utility-scale generation, energy trading, grid operations, or need one vendor covering both solar and wind.

---

2. Solcast — especially compelling for solar

Solcast is much more specialized than a generic weather API. Its forecasts combine satellite observations, cloud tracking and weather models, with forecasts from 5 minutes to 14 days ahead and 5–60 minute granularity.www.solcast.com

It also has dedicated PV power models, including models that can be trained using an asset's historical production data.solcast.com

This distinction matters: cloud/irradiance forecasting is often more important to PV production than generic temperature/weather accuracy.

Solcast solar forecasting API

Particularly interesting if: solar PV is your primary technology and you care about intraday/short-horizon forecasting.

---

3. Vaisala / Xweather

Vaisala has dedicated renewable-energy products covering wind and solar forecasts, historical data, asset-specific forecasting and regional forecasting.www.vaisala.com

Its current renewable API offering includes hub-height wind speed and power forecasts, plus solar GHI/POA and generation forecasts. For North American regional markets, it supports areas including ERCOT, PJM, MISO, SPP, CAISO and NYISO.docs.vaisala.com+1

Particularly interesting if: you're operating in North American electricity markets or need utility-grade weather + renewable forecasting.

---

4. The Weather Company

The Weather Company now has APIs specifically designed for renewable energy. Its solar API provides 15-day hourly GHI/DNI forecasts, while its wind API provides wind speed/direction and air density at a caller-specified height—useful because wind turbine production depends heavily on conditions at hub height rather than standard 10-m weather observations.developer.weather.com+1

It also offers a 7-day, 15-minute solar forecast, which is useful for intraday applications.docs.vaisala.com+2

Particularly interesting if: you want high-quality weather inputs but intend to build your own PV/wind production model.

The Weather Company Renewable Energy APIs

---

5. Tomorrow.io

I'd consider Tomorrow.io when the weather API is going to be part of a broader software/ML platform. It offers a large collection of weather variables and high-frequency forecasts, with a developer-oriented API. Independent 2026 comparisons highlight its broad data layers and frequent updates.apiscout.dev

The trade-off is that you're generally getting excellent weather inputs rather than a highly specialized, plant-calibrated renewable-power forecast.

Tomorrow.io Weather API

---

6. Open-Meteo — excellent for prototyping

For an initial research/ML pipeline, Open-Meteo is worth considering because it provides access to multiple numerical weather models without the complexity of an enterprise meteorological contract.

I'd use it to build and benchmark your forecasting architecture, then compare its predictions against a specialist provider before deploying a production system.

Open-Meteo API

---

What I'd choose by use case

Solar PV forecasting:
Solcast + Meteomatics would be the two I'd benchmark first. Solcast is particularly specialized around irradiance/cloud movement and PV forecasting, while Meteomatics gives you a broader meteorological/model ecosystem.www.meteomatics.com+1

Wind forecasting:
I'd investigate Meteomatics, Vaisala and The Weather Company, paying particular attention to hub-height wind, air density, turbine-level forecasts and model ensembles.www.meteomatics.com

Solar + wind in one platform:
Meteomatics is particularly compelling because the same API can supply the weather inputs and plant/portfolio generation forecasts.www.meteomatics.com+1

Building your own ML forecasting model:
Meteomatics, The Weather Company or Open-Meteo give you useful raw meteorological inputs; I'd benchmark them rather than assuming the generic weather provider with the best overall forecast is best for power prediction.

Production trading / grid operations:
I'd prioritize Meteomatics, Solcast and Vaisala, because they have renewable-specific forecasting products rather than treating renewable generation as a simple downstream application of generic weather data.

One important caveat

Don't benchmark these APIs primarily on weather forecast accuracy. Benchmark them on power forecast error at your actual sites—for example:

• 5/15-minute ahead
• 1-hour ahead
• intraday
• day-ahead
• nMAE / nRMSE
• bias
• ramp-event accuracy
• P50/P10/P90 performance if probabilistic forecasts matter

A provider can have excellent temperature forecasts and still produce mediocre PV forecasts if its cloud/irradiance prediction isn't good enough. Conversely, a renewable-specialist provider may outperform a generic weather API despite having similar headline weather accuracy.

If you tell me (1) solar vs. wind, (2) country/market—e.g. ERCOT, (3) forecast horizon, and (4) roughly how many MW/sites, I can do a more quantitative Meteomatics vs. Solcast vs. Vaisala vs. Weather Company comparison, including API resolution, historical/reforecast availability, pricing model, and what I'd test in an A/B forecast benchmark.

Predicting renewable energy production (solar and wind) requires weather data with high temporal granularity (e.g., 15-minute to hourly intervals), precise spatial resolution, and specialized metrics like GHI (Global Horizontal Irradiance), DNI, cloud-tracking aerosols, and hub-height wind speeds (1 0 0 m+ above ground).

The industry leaders providing specialized weather data and forecasting APIs tailored explicitly for renewable energy management include:

• Solcast (A DNV Company) : Widely recognized as a gold standard for solar resource assessment and tracking. Solcast uses satellite data and advanced atmospheric modeling to provide high-resolution irradiance, aerosol, and PV power forecasting APIs. Because it is integrated into DNV, its data is heavily trusted ("bankable") for financial and operational yield assessments.[solcast.com](https://solcast.com/)[[2](https://www.g2.com/products/visual-crossing-weather-api/competitors/alternatives)](https://www.g2.com/products/visual-crossing-weather-api/competitors/alternatives)[[3](https://developer.weather.com/docs/renewable-energy-package)](https://solcast.com/)
• Meteomatics : Known for its ultra-fast and flexible Meteorological API (Meteomatics API) , which updates weather models up to 280 times daily. They specialize in hyper-local, high-resolution data and direct power-output forecasting for solar, wind, and hydro assets, making them a favorite for energy traders and grid operators managing live plant portfolios.
• The Weather Company (IBM) : Offers a dedicated Renewable Energy API Package featuring granular 15-minute intraday solar/irradiance forecasting and height-specific wind forecasts (air density, wind speed, and direction at precise turbine heights). It is built for day-ahead market participation and real-time grid balancing.[solcast.com](https://developer.weather.com/docs/renewable-energy-package)
• Tomorrow.io : Offers a next-generation weather and climate security platform driven by proprietary radar and satellite data. Their API delivers rich data layers (over 80+ parameters) optimized for operational decision-making, energy asset management, and anticipating weather-driven anomalies that impact power generation.
• Google DeepMind (WeatherNext / Cloud-based AI Models) : Though historically internal or research-focused, Google's advanced AI weather forecasting models (like WeatherNext) have introduced hyper-localized predictions engineered explicitly for 100-meter wind speeds and solar radiation tracking, shifting the paradigm toward AI-driven meteorological forecasts for clean energy grids.[solcast.com](https://blog.google/innovation-and-ai/models-and-research/google-deepmind/introducing-weathernext-3/)

If you're building a forecasting tool or managing an asset, tell me:

• Are you focusing more on solar, wind, or a hybrid setup?
• Do you need data for intraday trading/balancing or long-term yield assessment?

I can help you narrow down which provider fits your technical and budget requirements best.

If your goal is forecasting solar/wind generation rather than generic weather, I’d shortlist providers based on forecast resolution, irradiance and hub-height wind quality, historical/hindcast data, ensembles, and whether they provide power forecasts rather than just meteorological variables.

My practical shortlist

For a commercial renewable forecasting platform: start with Meteomatics. It is unusually well aligned with the actual problem because it provides both the meteorological inputs and ready-made renewable generation forecasts. Its API exposes solar irradiance, hub-height wind and other energy variables, while its managed services can produce asset- and portfolio-level forecasts.Meteomatics+1

For solar specifically: evaluate Solcast alongside Meteomatics. A solar-only provider can be attractive because irradiance forecasting is sufficiently specialized that generic weather APIs aren't necessarily interchangeable.

For building your own forecasting/ML stack cheaply: Open-Meteo is worth testing first. Its ECMWF API provides 9-km hourly IFS forecasts and variables including 100/200-m wind and GHI, DNI, DHI and global tilted radiation. It also exposes individual historical model runs, which is particularly useful for hindcast/backtesting without accidentally using information that wasn't available at forecast time.Open Meteo+1

What matters most for renewable forecasting

Don't choose based primarily on the number of weather variables or API call limits. I'd benchmark providers on:

• Solar: GHI, DNI, DHI, cloud cover, aerosols, albedo, and ideally satellite-derived irradiance.
• Wind: wind speed/direction at the actual turbine hub height, not just 10-m wind.
• Temporal resolution: 15-minute or hourly data for intraday forecasting.
• Spatial resolution: important for individual wind/solar sites, especially complex terrain.
• Forecast horizons: nowcast → intraday → day-ahead → multi-day.
• Forecast ensembles: extremely useful for probabilistic generation forecasts and trading/risk management.
• Hindcasts: essential if you're training ML models and need realistic historical forecasts rather than reanalysis.
• Model diversity: ECMWF, GFS, ICON and/or proprietary/AI models can let you build an ensemble rather than betting on one NWP model.
• Asset modeling: panel orientation/tracking, turbine power curves, wake effects, availability, icing/snow, etc.
• Observations: site weather stations and real production data can materially improve forecasts.
• API/SLA: particularly important if the forecast feeds market bids or grid dispatch.

One important distinction: weather forecasting accuracy isn't the same thing as power forecasting accuracy. A provider can have excellent temperature/wind forecasts while producing mediocre MW forecasts if its conversion from weather → plant output isn't calibrated to your particular assets.

For example, Meteomatics explicitly supports plant-specific solar models incorporating panel orientation, tilt, capacity and tracking, and can refine forecasts using live plant data.Meteomatics

If you're building the forecasting model yourself, I'd probably benchmark Meteomatics vs. Open-Meteo/ECMWF vs. Solcast on the same 3–12 months of historical forecast vintages, then measure MAE/RMSE and bias in MW, not merely weather-variable error. That will tell you much more than generic API comparisons.

What matters most for renewable forecasting

For renewable-energy production forecasting, I’d look beyond generic weather APIs. The important differentiators are irradiance, hub-height wind, forecast ensembles, spatial/temporal resolution, historical reanalysis, and—ideally—direct power-forecasting capabilities.

Providers worth evaluating

My shortlist for renewable generation

1. Meteomatics — strongest specialized option

Meteomatics is particularly interesting if you're building a serious forecasting system rather than simply displaying weather. Its API provides 1,800+ parameters, historical data back to 1940, more than 110 weather models/sources, and downscaling to 90 m.Meteomatics+1

More importantly, it exposes renewable-specific variables: solar irradiance, tilted-surface radiation, hub-height wind, air density, icing, etc. It can also calculate theoretical wind/solar power using turbine and PV-system characteristics.Meteomatics+1

For solar, it can combine weather models, satellite data and plant-specific information to produce plant-level forecasts, including forecasts updated at 15-minute intervals.Meteomatics

2. DTN — particularly relevant for energy-market operations

I'd put DTN on the RFP/benchmark list if your application involves power trading, grid balancing, or commercial renewable operations. It has a dedicated renewables offering rather than treating renewable forecasting as merely another weather-API use case.Meteomatics

3. Tomorrow.io — good modern API alternative

Tomorrow.io is attractive if developer experience, weather-event detection and operational nowcasting are important. It is more of a general weather-intelligence platform than a renewable-generation specialist, so I'd benchmark its irradiance and wind forecasts against a specialist provider before committing.

What matters most for your model

For solar PV, I'd specifically require:

• GHI, DNI and DHI
• Cloud cover at multiple levels
• Aerosol/visibility information where available
• Temperature
• Snow/precipitation
• Satellite/radar nowcasting
• 5–15 minute data for short-term forecasting
• Hourly or sub-hourly day-ahead forecasts
• Historical weather/reanalysis data for model training

For wind, I'd require:

• Wind speed at the actual turbine hub height, not just 10 m
• Wind direction
• Air density
• Temperature and pressure
• Turbulence/gust information where available
• Multiple NWP models
• Ensemble/probabilistic forecasts
• 5–15 minute intraday updates
• Turbine power-curve information

Meteomatics, for example, explicitly supports wind forecasts at arbitrary heights from 10 m to 20,000 m and can calculate output for specific turbine models.Meteomatics+1

One important architectural point

If you're building your own ML forecasting model, I wouldn't automatically choose the provider advertising the highest "weather accuracy." I'd benchmark providers on generation forecast error at your actual sites.

A useful setup is:

Weather APIs → feature engineering → PV/wind physics model → ML correction → production forecast

Then evaluate MAE, RMSE, nMAE/nRMSE and bias separately for:

• 0–6 hour nowcast
• 6–24 hour intraday
• 24–48 hour day-ahead
• seasonal/long-range forecasts

You may even find that a multi-provider ensemble beats any individual weather source.

For a production system, my initial evaluation would therefore be Meteomatics + DTN + Tomorrow.io, with OpenWeather/Open-Meteo as lower-cost baselines. Meteomatics is particularly compelling when you need the weather data itself to be highly renewable-specific rather than merely general-purpose.Meteomatics+1

If you tell me whether you're forecasting solar, wind, or both, and your forecast horizon (e.g. 15 minutes, day-ahead, or 7 days), I can narrow this down to the most appropriate APIs and compare coverage, resolution, historical data, API limits, and likely pricing.

If your goal is forecasting actual renewable generation rather than simply displaying weather, I’d shortlist the providers differently from the usual consumer weather-API rankings.

My top choices

1. Meteomatics — my default choice

For a serious renewable forecasting platform, Meteomatics is probably the first vendor I'd evaluate.

It combines numerous NWP/AI/ensemble sources and provides very high-resolution data. More importantly, it has renewable-specific inputs such as:

• GHI, DNI and DHI / tilted-surface irradiance
• Wind at relevant hub heights
• Temperature, cloud cover and atmospheric variables
• Historical, real-time and forecast data
• Solar and wind generation forecasts
• Asset and portfolio-level forecasting

It can also deliver ready-made plant forecasts, rather than forcing you to build the weather-to-power layer yourself. Its solar service, for example, incorporates plant configuration and historical/live production data and can update forecasts every 15 minutes.Meteomatics+1

meteomatics.com

2. Solcast — particularly strong for solar

If you're forecasting PV production, I'd put Solcast on the shortlist even if you ultimately choose a broader weather provider.

The important distinction is that you're not merely asking:

"What's the cloud cover at this coordinate?" You're asking:

"How much power will this PV plant produce at 14:15 tomorrow?" A specialized solar provider can be advantageous because irradiance, cloud movement, satellite observations and PV-system characteristics can be incorporated directly into the forecast.

3. Vaisala — particularly compelling for utilities

I'd seriously evaluate Vaisala if you're dealing with:

• Utility-scale wind farms
• Large solar fleets
• Grid injection forecasting
• ISO/RTO markets
• Day-ahead/intraday trading
• Operational dispatch

This is less of a generic developer-weather-API decision and more of an enterprise meteorology/energy forecasting decision.

What matters more than the API itself

For renewable forecasting, I wouldn't choose based primarily on API uptime, number of endpoints, or developer friendliness. I'd benchmark vendors on:

1. Forecast error at your actual sites — MAE/nMAE and bias.
2. Forecast horizons — nowcast, 1–6 hour, day-ahead and multi-day.
3. Temporal resolution — ideally 5–15 minutes for intraday applications.
4. Solar variables — GHI, DNI, DHI, cloud optical properties and tilted-plane irradiance.
5. Wind variables — especially wind speed/direction at hub height, not merely 10 m.
6. Ensemble/probabilistic forecasts — valuable for trading and battery optimization.
7. Historical weather + actual generation — essential for training and backtesting.
8. Site-specific modeling — terrain, turbine/PV configuration, tracking, wake effects, etc.
9. Forecast update frequency — particularly important for intraday trading.
10. Data licensing and SLA — surprisingly important once you're operating at utility scale.

My recommendation by use case

• Solar PV forecasting: Solcast + Meteomatics should be your first comparison.
• Wind forecasting: Meteomatics + Vaisala + DTN.
• Solar + wind portfolio: Meteomatics is my first evaluation.
• Energy trading / bidding: Meteomatics, Vaisala and DTN.
• Build your own ML forecasting model: Meteomatics or Tomorrow.io.
• Prototype / low budget: OpenWeather or Weatherbit.
• prioritize rather than a generic weather API.

One important point: the best weather API isn't necessarily the provider with the best renewable-power forecast. If you have historical plant output, a strong architecture is often weather provider → physical PV/wind model → site-specific ML correction → probabilistic generation forecast. That lets you exploit the weather provider's raw data while retaining control over the part that actually predicts MW.

If you tell me whether you're forecasting solar, wind, or both, and whether this is for one site, a portfolio, or energy-market bidding, I can narrow this to the top 3 APIs and compare their data resolution, forecast horizons, historical data, pricing model, and API capabilities.

The top providers of weather data APIs built specifically or optimized for renewable energy prediction include Solcast, Meteomatics, Xweather , and Tomorrow.io . These platforms offer high-resolution atmospheric data, specialized solar irradiance tracking, hub-height wind metrics, and direct power-conversion forecasting models.

Comparison of Top Renewable Weather Data APIs

Breakdown of Leading Providers

• Solcast : Focuses heavily on the solar and renewable sector, offering live tracking, historical data, and forecasting derived from satellite imagery and atmospheric modeling. It features built-in power forecasting engines that convert irradiance directly into estimated PV output.solcast.com [solcast.com](https://solcast.com/)
• Meteomatics : Known for its blazing-fast RESTful API capable of pulling massive time-series data instantly. It bridges raw meteorology with ready-to-use power generation estimates, mapping data to exact coordinates or grid polygons for wind and solar farms.meteomatics.com [solcast.com](https://www.meteomatics.com/en/energy-forecasting/)
• Xweather : Delivers robust enterprise infrastructure with high spatial resolution (<10km). Its AI-driven forecast adjustments improve accuracy over standard numerical weather prediction (NWP) models, which helps mitigate unexpected renewable generation dips.xweather.com []()

If you'd like to narrow down the best choice, please share:

• Are you focusing primarily on solar, wind, or a hybrid portfolio?
• Do you need raw meteorological data (like irradiance and wind speed) or ready-made power output forecasts?

Predicting renewable energy production (solar, wind, and hydro) requires high-resolution weather data, precise temporal granularity (such as 15-minute intervals), and specialized parameters like solar irradiance (GHI, DNI, DHI) and hub-height wind speeds.developer.weather.com [developer.weather.com](https://developer.weather.com/docs/renewable-energy-package)[[2](https://www.meteomatics.com/en/energy-forecasting)](https://www.meteomatics.com/en/energy-forecasting/)

The leading providers offering dedicated weather data APIs tailored for renewable energy forecasting and grid management are outlined below:

1. Solcast
   • Overview: A specialized global provider built specifically for the renewable energy and solar forecasting industry. It tracks millions of locations worldwide with high-resolution tracking.
   • Best For: Solar asset generation forecasting, site-feasibility resource assessment, and tracking soiling/particulate matter impacts.
   • Key Features: High-resolution cloud-tracking and irradiance data via Solcast APIs, direct data transfer, and specialized operational power forecasting models.solcast.com [developer.weather.com](https://solcast.com/)[[2](https://www.meteomatics.com/en/energy-forecasting)](https://solcast.com/)
2. Meteomatics
   • Overview: Widely praised for its high-performance RESTful Weather API, Meteomatics aggregates multiple global and high-resolution local weather models, downscaling them to precise coordinates.
   • Best For: Energy trading, real-time grid balancing, and direct asset-level power generation outputs.
   • Key Features: Access to hub-height wind speeds, solar irradiance, and tailored solar/wind generation forecasts delivered in flexible formats like JSON, CSV, or NetCDF via Meteomatics Energy Forecasting.[developer.weather.com](https://www.g2.com/products/visual-crossing-weather-api/competitors/alternatives)[[2](https://www.meteomatics.com/en/energy-forecasting)](https://www.meteomatics.com/en/energy-forecasting/)
3. The Weather Company (IBM / Weather.com)
   • Overview: Offers an enterprise-grade Renewable Energy API Package built on proprietary forecasting tech with global coverage.
   • Best For: Day-ahead and extended planning, as well as intraday trading.
   • Key Features: 15-day hourly solar/wind forecasts and high-resolution 15-minute intraday solar irradiance blocks (tracking air density, wind direction/speed at specific heights above ground level) available through The Weather Company Developer Portal.developer.weather.com [developer.weather.com](https://developer.weather.com/docs/renewable-energy-package)
4. Vaisala Xweather
   • Overview: Combines advanced Numerical Weather Prediction (NWP) models with AI-powered forecasting to deliver high-accuracy micro-weather and hazard data.
   • Best For: Operational safety, high-hazard detection (lightning, hail, extreme winds), and precise localized forecasting.
   • Key Features: Ultra-low latency data updates and sub-10km resolution tailored for energy infrastructure monitoring via the Vaisala Xweather API.[developer.weather.com](https://www.xweather.com/blog/top-weather-apis-for-production-2026)
5. Visual Crossing & OpenWeather
   • Overview: More generalized enterprise weather data platforms that feature extensive historical archives and multi-model forecasting.
   • Best For: Prototyping, historical yield analysis, and budget-conscious development.
   • Key Features: Access to long-term historical records and standard current/forecast endpoints via Visual Crossing and OpenWeather.xweather.com [developer.weather.com](https://www.xweather.com/blog/top-weather-apis-for-production-2026)[[2](https://www.meteomatics.com/en/energy-forecasting)]()

To help narrow down the best fit, tell me:

• Are you focusing primarily on solar, wind, or a hybrid portfolio?
• Do you need raw meteorological data to run through your own internal models, or ready-to-use power output predictions?

If your goal is predicting renewable-energy production, I’d choose a provider differently from someone building a generic weather app. The important things are irradiance/cloud forecasts for solar, hub-height wind forecasts for wind, high temporal resolution, historical data for model training, and ideally asset-specific power models.

My shortlist

1. Solcast — my first choice for solar

solcast.com is unusually focused on renewable energy rather than generic weather.

Its solar forecasts combine satellite observations, cloud tracking and weather models, with forecasts from 5 minutes ahead through 14 days, updates every 5–15 minutes, and irradiance forecasts at high spatial/temporal resolution.Solcast+1

More importantly, Solcast provides PV power models, so you can go from weather → irradiance → expected plant output rather than building everything yourself. Its higher-end models can be trained/tuned using production data.Solcast

Choose it if: you're forecasting solar farms, rooftop PV, distributed solar, or solar-heavy portfolios.

2. Meteomatics — best overall for serious renewable forecasting

meteomatics.com would probably be my choice if you're building a platform covering solar + wind + hydro.

It aggregates 100+ weather models/sources, offers very high-resolution data, and exposes both raw meteorological variables and ready-made generation forecasts. Its energy offering supports individual assets, portfolios, regions and virtual power plants.Meteomatics+1

For wind, it can provide wind parameters at hub height and model turbine/farm production; for solar, it provides irradiance and plant-level generation forecasts.Meteomatics+1

Choose it if: forecast accuracy, multiple renewable technologies, high resolution and enterprise integration matter more than minimizing API cost.

3. Tomorrow.io — good API-first alternative

tomorrow.io is attractive if your team primarily wants a modern weather API with strong real-time/forecast capabilities.

It isn't as renewable-specialized as Solcast, but it can be a good foundation when weather forecasting is only one component of a larger energy platform. Independent 2026 comparisons put it among the stronger general-purpose commercial weather APIs.Meteomatics+1

4. DTN — particularly interesting for energy trading

dtn.com is worth serious consideration if your application is tied to power markets, trading, grid operations, or utility decision-making. Its strength is less "developer-friendly weather API" and more operational/decision-grade meteorological data and energy services.

5. Open-Meteo — excellent for experimentation

open-meteo.com is a very good choice for building a prototype or research pipeline without committing to an expensive commercial provider. It gives you access to multiple weather models and useful variables for developing your own solar/wind models.

I wouldn't make it my first choice for a mission-critical trading or grid application without doing substantial validation. A current 2026 comparison similarly characterizes it as particularly useful for research/prototyping rather than mission-critical production.Meteomatics

What I'd actually use

For solar forecasting: Solcast → Meteomatics → Tomorrow.io

For wind forecasting: Meteomatics → DTN → Tomorrow.io

For a platform covering solar + wind + hydro: Meteomatics is probably the strongest single-vendor choice.

For a research/ML prototype: Open-Meteo, then benchmark against Solcast or Meteomatics before going into production.

One important point: don't select purely on forecast weather accuracy. For renewable production, you want to benchmark power forecast error at your actual sites—e.g. normalized MAE/RMSE for 15-min, hour-ahead, intraday and day-ahead forecasts. A weather provider can have excellent temperature forecasts while being mediocre at predicting PV output because cloud movement and irradiance are the dominant problem.

If you tell me solar vs. wind, geography, forecast horizon (e.g. 15 min/day-ahead), and approximate number of sites, I can narrow this to the 2–3 APIs I'd actually recommend and compare their pricing, resolution, historical depth, and API limits.