The number of sunspots is a great indicator of solar output. That is, the more sunspots there are, the higher the sun’s energy output. This has effects on cosmic rays reaching Earth, the Earth’s climate, and even how well radio communications work. Let’s take a look (courtesy of at the number of sunspot free days over the last few years:

2020 total: 145 days (74%)
2019 total: 281 days (77%)
2018 total: 221 days (61%)
2017 total: 104 days (28%)
2016 total: 32 days (9%)
2015 total: 0 days (0%)
2014 total: 1 day (<1 p="">2013 total: 0 days (0%)
2012 total: 0 days (0%)
2011 total: 2 days (<1 p="">2010 total: 51 days (14%)
2009 total: 260 days (71%)
2008 total: 268 days (73%)
2007 total: 152 days (42%)
2006 total: 70 days (19%)

You can see that solar activity is cyclical, and you can see that we have been sunspot free for the majority of the time for the past three years. The last solar minimum (2008-2009) only lasted for two, with a seven year gap to the current one.

Solar cycles are normally 11 years long, but can last as long as 14 years. The current cycle began on January 4, 2008. The maximum sunspot number for this cycle was the lowest since cycles 12-15 (1878-1923, also known as the Dalton Minimum). So far this year, the Sun has been blank 76% of the time, a rate surpassed only once before in the Space Age. Last year, 2019, the Sun was blank 77% of the time. Two consecutive years of record-setting spotlessness adds up to a very deep solar minimum.

Long periods of low solar output are followed by colder weather on Earth

Categories: Uncategorized