Weather data sources

In addition to the Weather Data included in PVsyst, there are many weather data sources available from the Web or by other means. PVsyst includes a tool for easily importing the most popular ones. These are summarized in the tables below, and we have performed a comparison between their results.

Sources of Weather data

Hourly values

• Vaisala (previously 3Tier) provides hourly data measured by satellites, recent, for most locations on the earth (up to 80000 named locations). Paid service.
• Explorador Solar provides hourly data measured by satellites, for Chile, in the form of time series of the 2004-2016 period and also TMY. For free.
• Meteonorm hourly values are not measured, but synthetic data constructed in the same way as the synthetic hourly values in PVsyst from monthly values. Hourly time series for the period 2015-last month based on satellite data and ERA5 reanalysis. Additional product (not included in PVSyst).
• NREL's National Solar Radiation Database provides Typical Meteorological Year files which are compilations of measured hourly data chosen among 1961-1990 (TMY2) or 1991-2005 (TMY3), for 1020 locations in the US. This USTMY2/3 format is also a standard used for other kinds data, used for example as input for the SAM software (Solar Advisor Model).
• NREL's for India provides data for India, for the 2002-2011 time period coverage, in TMY3 format.
• NREL's NSRDB Data Viewer provides Typical Meteorological Year files which are compilations of measured hourly data and (sub-)hourly time series from 1998-2021 for PSMv3 and 2000-2014 for Suny. The files provided are in SAM CSV file format.
• PVGIS provides Typical Meteorological Years for geographical location around the world with data from CM-SAF, SARAH and NSRDB. Available at geographical site creation.
• ReuniWatt provides hourly data measured by satellites, recent, for any location on the earth. Paid service.
• Soda-Helioclim provides data in hourly values, measured by METEOSAT, since February 2004. But these data are not free. Files usually provided in PVsyst standard format.
• SolarAnywhere® provides bankable solar resource data for project finance. Available for specific sites on a 1 km x 1 km or 10 km x 10 km basis from 1998 to the present hour depending on geographic availability.
• Solargis provides hourly data measured by satellites, recent, for any location on the earth. Paid service.
• SolarProspector, now decommissioned, was providing hourly values, including ambient temperature, for any location in the USA, for free. PVsyst still allows the processing of Solar Prospector files.
• Solcast provides TMY and timeseries data measued by satellites, for any location on the earth. Paid service.
• Vortex Solar provides hourly data measured by satellites, recent, for any location on the earth. Paid service.
• 3E provides Typical Meteorological Years (TMY) for geographical location around the world with data from Meteosat, GOES and Himawari.

Summary of sources in Hourly values

Monthly values

• Meteonorm monthly irradiance data are available for about 1'200 "stations", as averages of 1960-1991 (and also 1981- 2000 in version 6.1). All "stations" (i.e. with irradiance measurements) of the main European countries are referenced in the PVsyst database. Data for any other site may be obtained by interpolation (usually between the 3 nearest "stations").
• NASA-SSE Data (Surface Meteorological and Solar Energy Programme) hold satellite monthly data for a grid of 1°x1° (111 km) covering the whole world, for a 10 years period (1983-1993).
• Solargis provides also monthly data measured by satellites, recent, for any location on the earth. For pay.

Summary of weather data sources in Monthly values

NB: All these monthly data are imported as geographical sites files *.SIT, and will require the construction of Synthetic Generated hourly data files for being used in the simulation.

NB: Monthly values are often given as averages over several years.

But due to the variability, it doesn't make sense to average weather data in Daily or Hourly values. Such data are always issued from real measurements at a given site (or eventually from satellite photographies).

In the same way, it is also not reliable to interpolate hourly values between different sites.