Typical Meteorological Year

Typical Meteorological Year (TMY) data for solar energy simulations and yield analysis

A collation of historical weather data derived from a multi-year time series selected to present the unique weather phenomena with annual averages that are consistent with long term averages.


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 real time and forecast data tracks and forecasts real clouds at a resolution of 1-2km and 5 minutes. Our irradiance and PV power data is updated every 5 to 15 minutes. Aerosol and albedo effects are explicitly treated.


Integrate directly with your PV software, or upload with multiple file format options

Solcast data is available directly in PVSyst, SAM, PlantPredict and PV*Sol. Support for other softwares via industry standard data formats.


Multiple probabilistic scenarios available for due diligence and solar resource assessment

Direct API download for TMY P50 data. TMY PXX scenarios (P75, P90, P95) downloads through the Solcast API Toolkit. Multiple file types supported (CSV, PVsyst, TMY3, SAM).


Dataset supported by independent global validation

The data has low uncertainty and a quantified error range, making the data suitable for resource assessment, yield analysis, financial modelling, and any application requiring precision irradiance data.

TMY Data Specifications

Geographic coverage

Global (note: data quality is lower in remote ocean and polar regions)

Temporal resolution

15, 20,30 or 60 minutes (period-mean values)

Spatial resolution

90m to 2km (elevation, irradiance and cloud parameters, over all non-polar continental areas and nearby islands)

27km (other parameters, and polar or remote oceanic regions)

Pxx (Probability of exceedance)

P50, P75, P90, P95

Data parameters

The following data parameters are available.

  • Global Horizontal Irradiance (GHI) (W/m2)^
  • Direct Normal Irradiance (DNI) (W/m2)^
  • Diffuse Horizontal Irradiance (DHI) (W/m2)^
  • Global Tilted Irradiance (GTI) (W/m2)^
  • Advanced PV Power Output (MW)^
  • Rooftop PV Power Output (kW)^
  • Cloud Opacity (%)
  • Air Temperature (°C)
  • Solar Zenith Angle (°)
  • Solar Azimuth Angle (°)
  • Albedo (%)
  • Wind Speed (10m) (m/s)
  • Wind Speed (100m) (m/s)
  • Wind Direction (10m) (°)
  • Wind Direction (100m) (°)
  • Relative Humidity (%)
  • Precipitation Rate (mm/h)
  • Surface Pressure (hPa)
  • Precipitable Water (kg/m2)
  • Dewpoint Temperature (°C)
  • Snow Depth Water Equivalent (cm)
  • Snow Depth (cm)
  • Snow Soiling Loss - Rooftop (%)
  • Snow Soiling Loss - Ground Mounted (%)

^ Clear-sky scenarios also available for these parameters

Data access

API or Web download

Download wait time

No wait time

Data formats


Time zone

UTC (default for Solcast), longitudinal (default for SAM, PVsyst, TMY), or user-set

Historic Data Products

Time Series
The complete suite of irradiance and weather data required for effective monitoring, operation, and forecasting at your large-scale solar farm.
Typical Meteorological Year (TMY)
The complete suite of irradiance and weather data required for effective monitoring, operation, and forecasting at your large-scale solar farm.