Reliable solar irradiance forecasting is crucial for off-grid photovoltaic systems, and a new approach uses physics-informed state space models to improve accuracy. Traditional deep learning models have been plagued by issues such as temporal phase lags during cloud transients and incorrect predictions of nocturnal power generation. The new method incorporates atmospheric thermodynamics to generate more realistic forecasts, addressing the limitations of data-driven modeling. By accounting for physical constraints, these models can reduce errors and improve the overall stability of off-grid systems. This development has significant implications for the efficient operation of autonomous photovoltaic systems, particularly in remote or resource-constrained areas1. So what matters to practitioners is that this innovative approach can enhance the reliability and performance of off-grid energy systems, ultimately supporting the wider adoption of renewable energy sources.