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Solar Radiation Data

Accurate, solar radiation and weather data, with global coverage. Historical, real-time and forecast data, seamlessly delivered via API, including CSV download.

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Data Specifications


Core parameters:

  • Global Horizontal Irradiance (GHI)
  • Direct Normal Irradiance (DNI)
  • Diffuse Horizontal Irradiance (DIF, DHI)
  • Cloud Opacity
  • Temperature
  • Solar zenith angle
  • Solar azimuth angle

Historical and Recent data also includes:

  • Global Tilted Irradiance (GTI)
  • Wind Speed
  • Wind direction
  • Relative humidity
  • Surface pressure
  • Precipitable water

Forecast probabilities:

10th and 90th percentile forecasts provided for:

  • Global Horizontal Irradiance (GHI)
  • Direct Normal Irradiance (DNI)

Spatial coverage

All continents (Rapid update actuals and forecast data)

Global (forecasts)

Time granularity

Utility Scale Sites: 5, 10, 15, 20 or 30 minutes (period mean)

Other sites: 30 minutes (period mean)

Update frequency

Every 10 or 15 minutes

Time span (Forecast)

Present time to +7 days ahead

Time span (Realtime)

7 days ago to present time

Time span (Recent)

4 months ago to 2 days ago

Time span (Historical)

15 years ago to 2 days ago

  • Extended Evaluation Period
  • Welcome, early adopters!

    You are welcome to try all the features of the Solcast API in an extended Evaluation Mode until approximately March 2019. This includes the ability to add 1x new site, access Live and Forecast data, and download our ‘Recent’ historical data.

  • What happens in March 2019?

    At that time, if you wish to continue use of a priced product, you can choose to enter your credit card details and begin a 14 day free trial.

    If you’re a home hobbyist, a student or a public researcher then see our free offers, or contact us.

    If you’re a corporate customer, you can also contact us about our Full Service Solutions.

  • Historical Data
  • Contact us for pricing

    Or register now, to instantly evaluate our data and see free data samples

  • Free historical data for public researchers

    Includes free Recent and Historical data for up to 5 existing Solcast sites. Read more about this offer

  • Live and Recent Actuals (USD)
  • First 5 sites:


  • 6 or more sites:


  • API calls:

    100 API calls/site per day included.

  • Large numbers of sites:

    Contact Us or speak to one of our Full Service Partners to discuss options. We suggested you first consult our API Documentation to determine how many latitude/longitude based radiation requests you’ll require.

  • Forecasts (also includes Live and Recent Actuals) (USD)
  • Note:

    Weather/irradiance data comes included with Utility Scale Forecasts

  • First 5 sites:


  • 6 or more sites:


  • API calls

    100 API/site per day included.

  • Large numbers of sites:

    Contact us or speak to one of our Full Service Partners to discuss options. See our API Documentation for our latitude/longitude based radiation requests, then contact us to discuss pricing.

  • Self Service Only
  • Note:

    Prices listed here are for web self-service only. If you are interested in receiving any of the following additional services, contact us or speak to one of our Full Service Partners to discuss options:

    • Bespoke, edited or physically signed contracts
    • Ability to licence or re-sell our data
    • A service level agreement defining service levels and response times
    • 24/7 support services, including telephone support
    • Packages including general (non-renewables related) weather services
    • Accuracy guarantees
    • Special consulting projects requiring additional services or report writing

Frequently Asked Questions

Can I also access solar radiation forecasting and estimated actuals data, if I am using one of your other products?

Solar radiation forecasting data comes included with any purchase of our Utility Scale solar forecasting product.

What data fields are included in your solar radiation products?

Global, direct and diffuse irradiance, plus selected weather variables. For additional detail, review the specifications above or consult our documentation.

Do you offer plane of array radiation calculations?

No, not at this time. Consider our Rooftop Solar product as an alternative.