Comparing Solcast Historical and TMY data with alternatives

Compare Solcast historical and TMY products to Solargis, Meteonorm, Vaisala, and free data sources
Historical and TMY
How does Solcast compare to other data sources?

Solcast data was designed to be the most full-featured, most accurate source of irradiance and weather data for solar applications.

Paid alternatives to Solcast historical and TMY data including Solargis, SolarAnywhere, Meteonorm, 3E and Vaisala are generally harder to access and try, and less rich in API and data features. The alternatives are generally less accurate on most measures, and less comprehensively validated.

Free substitutes to Solcast including NREL NSRDB and PVGIS SARAH have data that is not bankable, ends more than two years ago, lacks many features, is not global in coverage and/or is not validated globally.

Read the Solcast Bankability Report published by DNV here.

Solcast
Solargis
Meteonorm
Vaisala
SolarAnywhere
Considered Bankable? North America only, 1km data only
Free trial with instant access and data download?
Download wait time 1-3 seconds 5 minutes to 48 hours 1 minute 5 minutes to 24 hours 5 minutes
Mean Bias Error (GHI) 0.33% +0.3% -0.67% 0.12% 0.01%
Standard Deviation of Bias (GHI) ± 2.47% ± 3.0% ± 6.99% ± 4.43% ± 2.13%
90% Bias uncertainty range -3.74% to 4.40% -4.7% to +5.3% -12.17% to +10.83% -6.5% to 7.1% Insufficient validation sites
Mean Hourly RMSE (GHI) 15.99% 16.08% 17.80% 20.77% 20.60%
Comprehensive, global, independent validation
Validation Sites 207 228 85 196 54
Finest time resolution of satellite-based irradiance 5 minutes 15 minutes 60 minutes 10 minutes 5 minute
Real time data available?
Excludes older, less reliable satellites

For more detail read the full comparison of Solcast against some commonly used datasets in the solar development community:

Free sources comparison

Solcast NREL NSRDB PVGIS SARAH
Finest time resolution of real satellite-based irradiance 5 minutes 5 minutes 60 minutes
Latest data available Real-time Ends 2021 Ends 2020
Independently validated globally
Validated at 100+ sites globally
Largest validation study: # of sites 207 70 50
GHI Bias – Global Mean 0.33% 0.3% 0.7%
GHI Bias – Global Standard Deviation ± 2.47% ± 2.7% ± 3.2%
GHI Bias – 90% uncertainty range -3.74% to 4.40% Not reported Not reported
GHI Hourly RMSE – Global Mean 15.99% 18.47% 19.6%
Excludes older, less reliable satellites

For more detail read the full comparison of Solcast against some commonly used free datasets in the solar development community:

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.