TMY

TMY data is frequently used by solar engineers, as a data input to energy system simulations.

Solcast offers two variants of TMY: TMY P50 and TMY PXX (inclusive of P50, P75, P90, & P95).

Both of TMY P50 and TMY PXX can be accessed through our API Toolkit, and our TMY P50 files are available through a fast, low cost API service.

The TMY P50 API includes access to 2x free TMY files per month in our ‘Free Tier’ subscriptions, with paid options starting at $49 USD / month with no lock-in contract. See details on the Solcast pricing page.

If you are interested in TMY P50 API access, you can review our API docs here, to see if the service is a fit for your business.

You can access this API based service directly, after you sign-up for your free account in the Solcast API Toolkit.

About TMY Files

A TMY, or Typical Meteorological Year, is a collation of historical weather data for a specified location for a one year period.

The dataset is derived from a multi-year Time Series specifically selected so that it presents the unique weather phenomena for the location, and provides annual averages that are consistent with long term averages.

All TMY files contain exactly 8760 rows of data, each corresponding to an hourly period in an ‘average’, or ‘typical’ year. TMY data is frequently used by solar engineers, as a data input to energy system simulations.

TMY data specifications

Pxx (Probability of exceedance)Basic TMYExtended TMYAvailable on request
P50P50, P75, P90, P95Pxx
CoverageGlobal, except for ocean and polar regions
Spatial resolution of satellite data1-2 km
Time granularity60 minute
Timespan of database used to generate TMYJanuary 2007 to 7 days ago
Parameters
  • Global Horizontal Irradiance (GHI, W/m2)
  • Direct Normal Irradiance (DNI, W/m2)
  • Direct (Beam) Horizontal Irradiance (EBH, W/m2)
  • Diffuse Horizontal Irradiance (DIF, DHI, W/m2)
  • Global Tilted Irradiance (GTI, W/m2)
  • Cloud Opacity (%)
  • Albedo (%)
  • Solar Zenith angle (°)
  • Solar Azimuth angle (°)
  • Temperature (TEMP, °C)
  • Wind Speed (WS, m/s)
  • Wind Direction (WD, °)
  • Relative Humidity (RH, %)
  • Surface Pressure (AP, hPa)
  • Precipitable Water (PWAT, kg/m2)
  • Snow Depth (SWDE, cm)
  • Dew Point (DWPT, °C)
Files provided
  • Solcast standard CSV
  • PVsyst
  • SAM
  • TMY3
Time zone
  • UTC (default for Solcast)
  • Longitudinal (default for SAM, PVsyst, TMY)
Database update frequencyDaily (recent months are considered in TMY scenario)
Access method
Download wait time
  • API Toolkit Request form: Typically 1 to 9 minutes
  • Synchronous TMY P50 API: less than 100ms

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