Forecast.Solar’s Python library corrects hourly energy estimates that were shifted back by one period. Its current-hour value contained the previous hour’s energy, while the calculation used for Home Assistant’s next-hour sensor returned the current hour instead.
The correction follows the service’s timestamps, which mark the end of each measurement period. Tests cover hourly and fifteen-minute forecasts. It is Tagliax’s first contribution to the library; the separate remaining-energy-today calculation is unchanged.