Abstract
I discuss the impact factor of Space Weather for 2021, its small
decrease with respect to the number in 2020, and potential causes for
this decrease. The limitations of the impact factor are emphasized as
reported in past studies, in particular due to the large weight of
highly cited papers. For Space Weather, over several years, the median
number of citations received by a paper per year is close to the impact
factor at the time of publication, with very few papers receiving no
citations. I expect that, as the solar cycle ramps up, the impact factor
will start to grow again. Key Point Space Weather has an impact factor
of 4.29 in 2021, a 4% decrease as compared to 2020 but a 49% increase
as compared to 2017.