This graph looks at the electricity (measured in kWhs) produced in the last three days by McMillan's rooftop solar project. It is easy to see cloudy days or even cloudy hours on the graph. The Library uses about 60 kWhs when open on this graph and about 20 kWhs when closed, though that is higher when the air conditioning is operating.
On the right is a live measure of what is being produced right now. Passing clouds are visible on this.