[1][2] The solar cycle lasted 11.3 years, beginning in December 1855 and ending in March 1867.

The maximum smoothed sunspot number observed during the solar cycle was 186.2 (February 1860), and the starting minimum was 6.0.

[7] On September 1–2, 1859, the largest recorded geomagnetic storm occurred in what would be known as the Carrington Event.

[7][8] Aurorae were seen around the world, even over the Caribbean; those over the Rocky Mountains were so bright that their glow awoke gold miners, who began preparing breakfast because they thought it was morning.

Some telegraph systems continued to send and receive messages despite having been disconnected from their power supplies.