In the Potsdam record back to 1932 (https://t.co/DeifdDqgxN), there have only been 17 out of a possible 1051 months in which the Solar Ap Index was less than 5. Here are the occurrences:
— griteater (@griteater) August 14, 2019
1997: 1
2008: 2
2009: 9
2010: 2
2011: 1
2012: 1
2019: 1 (June)https://t.co/5tgBBR5g6z pic.twitter.com/cIFaPpYlCs