Spotless Days

Regular solar observers have noticed that since mid-2016, the Sun has occasionally been devoid of sunspots. These spotless disks have become a familiar feature as the solar cycle is transiting through its minimum, which has taken place in December 2019 (see for more information). The number of spotless days can vary significantly from one solar cycle transit to another. For example, during the previous minimum (around 2008), no less than 817 spotless days were recorded, whereas the minimum period leading into solar cycle 23 (around 1996) counted only 309 such blemishless days. As the new solar cycle 25 has started, several consecutive days and even weeks without sunspots will become less frequent. In order to have an idea on the total number of spotless days during this minimum transit, and how these numbers compare to past solar cycles, the SILSO folks created a “Spotless Days page” back in 2016. This page contains graphs and tables on the accumulated number of spotless days, stretches of spotless days, and comparisons to other solar cycles – all supplemented with a word of explanation.
The previous minimum surprised scientists and solar observers by being the deepest in nearly 90 years, and also this minimum is -once again- a very deep one. This “Spotless Days page” will continue to provide you with a front-row seat on the current status of the solar cycle minimum and the number of spotless days. Enjoy!

Last update: 5 July 2022

Next update: at the start of the next solar cycle transition (SC25-26)