There is a very useful solar forecasting tool that has been developed out of research at the Australian National University, and commercialised by Solcast. It can provide a solar forecast for any location.
They say “Solcast can forecast solar data for any location on Earth. Using five weather satellites and a growing suite of numerical weather models, Solcast generates over 600 million actual and forecast data points every hour.”
“For the majority of locations, Solcast Live and Forecast data is updated every 10 to 15 minutes at a resolution of 1 to 2 km.”
While primarily for large & commercial PV installation, home rooftop systems can access some services for free.
There is a “tuning” system available where machine learning is used on historical data, so forecasts can be more accurate. I was looking to use the forecast/tuning
facility but my system is setup with variable (manual) export limiting so not suitable for this.