yet September was a warm month

These two plots show our daily solar power generation in kWh, month by month.  The first plot shows the actual daily values (with some jitter applied to the horizontal position, to prevent points overlapping).  The second shows violin plots (box and whisker plots of median and quartile statistics, overlaying a kernel density plot, which is a smoothed version of the jitter plot).

August was a relatively cool month.  September was a relatively warm month, one of the warmest on record, in fact.  But it’s all relative.  The shorter days really have an effect, reducing the daily average.

You can see how the days are pulling in from the daily plots. The horizontal time axis runs from 3:00am to 9:00pm GMT. There is one line of data per day. Data is gathered every 5 minutes.  Each pixel represents the energy generation at the sample point. The colour indicates the energy generation in the relevant interval: darker colours indicate more energy.  No energy is generated at night!

So, our solar power system can detect the seasons!

You can find a full set of plots here.