SOLARFOR is among the most accurate tools on the market for solar power forecasting today. However, the uncertainty of the forecasts varies in time (for instance as a function of the cloud cover situation), and therefore SOLARFOR also offers reliable estimates of the uncertainty of the predictions. Reliable estimates of the uncertainty are crucial for knowing if a given the prediction is precise or not. It is well-known that estimates of the uncertainty are needed for obtaining optimal economical benefits of the forecasts. SOLARFOR is focusing on the short term markets, and the horizon is typically up to, say, 72 hours, but it can be changed to accomplish other needs.