Solar cycle 16

Solar cycle 16 was the sixteenth solar cycle since 1755, when extensive recording of solar sunspot activity began. The solar cycle lasted 10.1 years, beginning in August 1923 and ending in September 1933. The maximum smoothed sunspot number (monthly number of sunspots averaged over a twelve-month period) observed during the solar cycle was 78.1 (April 1928), and the minimum was 3.5. There were a total of 568 days with no sunspots during this cycle.

Newspaper reports during this period note effects on telegraph systems, but also (in March 1924, January 1926, October 1926, and October 1927) on radio transmission.