by Von Frank Bosse & F. Vahrenholt, January 30, 2019 in WUWT
Our sun was also very sub-normally active in December last year. We are writing the 121st month since the beginning of cycle number 24, in December 2008, and since 2012 (when we started the blog here) we could only reformulate the opening sentence once: In September 2017 when the sun was 13% more active than the long-term (since 1755) average.
All other months were below average. With the sunspot number (SSN) of 3.1 for the monthly average for December and a total of 24 days without any spot (throughout the second half of the month the sun was spotless) we are in the middle of the cycle minimum.
Fig. 2: The sunspot activity of our sun since cycle 1 (1755). The numbers are calculated by adding the monthly differences with respect to the mean (blue in Fig.1) up to the current cycle month 121.