by P. Gosselin from F. Bosse and F. Vahrenholt, June 18, 2017

In May the sun was very quiet as sunspot number was a mere 18.8, which is only 36% of what is typical for the month this far into the cycle. Seven days saw no sunspot activity at all.

The following chart shows the current cycle, Solar Cycle 24 (red), compared to the mean of the previous cycles (blue) and the similarly behaving SC 5 (black).

It’s clear that the current cycle is significantly weaker than the mean and far weaker than the cycles we saw throughout most of the warming 20th century.