Developer that works at Solcast here, hope others find this useful. Blog post with a tool to check the last 6 days of PV performance nearly anywhere in the world. Live data comes from 5 satellites. Tracks global cloud opacity and uses surface radiation estimates to model PV output. Handy to see if your rooftop PV system is performing at expected levels. Home page also has 1 day forecasts which are updated every 5-15 minutes depending on satellite coverage.