At the moment, we do not offer any logging functionality for users to assist in troubleshooting should there be any issues.

We highly recommend that you record and log responses from request that you make, which will simplify the troubleshooting process should you encounter any errors.

These logs, when provided to us, enable us to isolate the issue and provide you with the best information as to the cause of the error, and the next best steps.

Should you be unable to provide these logs, don’t fret, just provide us with as much information as possible, and we’ll do our best to help you resolve any issues.

No. One account is equivalent to one API key.

We use 2 different forecasting methods for different forecast horizons

1. 0 to +4 hours: Nowcasts - we use our proprietary Nowcasting models, which track images of real clouds using optical flow models. These update every 5-15 minutes depending on location, in Europe, it is every 15 minutes. That means you get a new forecast every 15 minutes, which runs for the next 4hrs
2. +4hrs to +14 days: NWP ensemble - we blend our Nowcasts into an ensemble of Numerical Weather Prediction (NWP) models which are trained on our live data and run from +4 hours to 14 days into the future

Please read our irradiance methodology for further detail here: https://solcast.com/irradiance-data-methodology

At this stage bifacial modules is not available for TMY Rooftop PV Power. If this changes in the future, it will be announced within the product updates notification.

Understanding the various Solcast products can be difficult. Below is a summary breakdown of Solcast difference between Live and Historic Data.

Live

• Product Data Period: -7 days to right now. Very high rate limits available.
• Data Source:
• Past 20 minutes: Nowcasts
• Beyond 20 minutes: Cloud data derived from satellite images (i.e. observations)
• NWP weather data is typically short-term forecasts from GFS/CAMS

Historic

• Product Data Period: 2007 to -7 days. Moderately high rate limits available.
• Data Source: Cloud data derived from past satellite images (i.e. observations).
• NWP weather data is typically from re-analysis datasets, e.g. ERA5/merra2

To Conclude

Both the live and historic data are far more similar than different. As irradiance and power data is primarily driven via cloud observations which in itself is provided by satellite data, it allows Solcast to provide very accurate measurements of data.

Live and historic data for a particular day may differ (e.g. querying the same day after 1 week, then 3 months later) because we continue to assimilate new data sources as they become available. Namely by reanalysing NWP data as they are received, this is then used for weather parameters and as inputs in our irradiance calculations. This incremental improvement enhances the accuracy of the data.

The general rule for "when should I query the data for my site" is: when you need it. The Solcast API always returns the best data available right now, and as time progresses more information comes in and we refine the data.

• /data/forecast and /data/live within a few hours of realtime change often as new satellite data comes in.
• /data/forecast for the dayahead typically update every few hours as new NWP input forecasts come in.
• /data/live and /data/historic typically change very slowly and will only update a few times, as the most important data (satellite observations) have already arrived.