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Typical Meteorological Year
Download a statistically representative “typical year” file built from 15 + years of satellite data for long-term yield modelling.
Overview
FORECAST solar Data
Plan with confidence – from 5 minutes to 14 days ahead
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High-resolution irradiance and PV power forecasts keep your planning sharp – from utility-scale dispatch to rooftop generation.
Solcast Forecast projects irradiance and PV power from five minutes ahead to 14 days out, with 5- to 60-minute granularity anywhere on the planet. Portfolio owners schedule maintenance when production dips; traders optimise day-ahead bids; grid planners model tomorrow’s net-load with confidence - all from the same reliable feed.
CLOUD AND IRRADIANCE TRACKING
Tracking the world's clouds in the finest detail
Designed for solar, from the ground up. Never rely on generic weather model data again. Solcast’s solar forecasts track and predict cloud movements at a resolution of 1-2km and 5 minutes, and are downscaled to 90-metre resolution. Aerosol and albedo effects are explicitly treated, just like in our live data.
DATA SPECIFICATIONS
Forecast data that actually meets your requirements
Forecast data spans from 5 minutes ahead up to 14 days ahead, issued every 5 to 15 minutes, with forecast intervals of 5 to 60 minutes – anywhere on Earth. Forecasts are built from a fusion of satellite observations, cloud-tracking algorithms and advanced weather models.
ACCURACY
Proven, industry-validated forecast accuracy
Our forecast accuracy beats global weather models by 25% (day-ahead) to 50% (hour-ahead). Hundreds of data scientists and engineers have confirmed our accuracy, and we're willing to guarantee it. Review our accuracy verification, or contact our team to access real past forecasts for your actual sites.
Data Access
Easy integration via API or browser download
Integrate the Solcast API directly into your systems via JSON or CSV. Relied upon by power system operators on four continents. API uptime of >99.99%, with very low latency. Bulk API requests available. SLAs available.
Product specifications
Geographic covereage
Global (note: far ocean and polar regions are coarser resolution)
Temporal coverage
+5 minutes to +14 days
Temporal resolution
5, 10, 15, 30 & 60 minutes (period-mean values)
Spatial resolution
90 meters (irradiance, PV power, snow soiling, cloud parameters, and other parameters across all regions)
Data parameters
The following data parameters are available.
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Irradiance Parameters
- Global Horizontal Irradiance*^ (GHI) (W/m2)
- Direct Normal Irradiance*^ (DNI) (W/m2)
- Diffuse Horizontal Irradiance*^ (DHI) (W/m2)
- Global Tilted Irradiance*^ (GTI) (W/m2)
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Solar Parameters
- Advanced PV Power Output *^ (MW)
- Rooftop PV Power Output *^ (kW)
- Solar Zenith Angle (°)
- Albedo Daily
- Snow Soiling Loss – Rooftop (%)
- Snow Soiling Loss – Ground Mounted (%)
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Weather Parameters
- Cloud Opacity * (%)
- Air Temperature (°C)
- Wind Gust (m/s)
- Wind Speed (10 & 100m) (m/s)
- Wind Direction (10 & 100m) (°)
- Relative Humidity (%)
- Surface Pressure (hPa)
- Precipitable Water (kg/m²)
- Precipitation Rate (mm/h)
- Dewpoint Temperature (°C)
- Snow Depth Water Equivalent (cm)
- Snow Depth (cm)
- Snowfall Rate (cm/h)
- Thunderstorm Potential – CAPE (J/kg)
^ Clear-sky values also available (no clouds, aerosols accounted for)
* Probabilistic scenarios available
View detailed parameter definitions in our API documentation.
Data access
API or Web download
Download wait time
API: synchronous requests. Web download: seconds.
File formats
CSV, JSON, PVsyst, SAM, TMY3
Data formats
Solcast standard, PVsyst (60 minute only)
Time zone
UTC, longitudinal, or user-specified fixed offset.
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See how our Live and Forecast data stack up - region by region, metric by metric - in our detailed performance validation.
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Frequently Asked Questions
What is solar forecast irradiance data?
Solcast’s forecast data predicts future solar irradiance from +5 minutes to 14 days ahead. We combine satellite cloud-tracking with advanced weather models to produce high-resolution forecasts that update every 5 to 15 minutes.
What is a solar nowcast?
Nowcasts are very short-term forecasts (up to 6 hours ahead) using real-time satellite imagery. Solcast’s nowcasts update every 5–15 minutes to give users actionable foresight before weather changes impact operations.
What is day-ahead forecasting?
Day-ahead forecasting predicts solar irradiance for the upcoming day, usually 0 to 24 hours in advance. Solcast provides probabilistic forecasting, including P10, P50 and P90, for day-ahead forecasts. These help gauge uncertainties and provide a range of possible outcomes for better decision-making, preventing inefficient power management, regulatory violations, unnecessary storage system cycles and more.
How accurate is Solcast forecast data?
Solcast data consistently beats global models with lower bias and better RMSE, MAPE and correlation. Our forecast engine blends real-time satellite observations with mesoscale weather models for maximum accuracy.
How can I access forecast data?
Forecast data is available via the Solcast API or Web Toolkit, with download options in JSON or CSV. All forecasts are available in UTC or custom timezones, and formatted for direct ingestion into your systems.
