Sunspots may or may not be involved. How’s that? LOL
Solar winds crashing into the upper atmosphere don’t create heat. At this point, there seems to be no hard answer to your question.
I believe the work of the famous Danish solar scientist, Professor Henrik Svensmark, in his seminal book, The Chilling Stars: A New Theory of Climate, wrote of this.
He basically stated the lessening of the solar wind would mean more cosmic radiation reaching Earth, and thus causing cloud formation, which then enhances albedo, and less warmth from the Sun to the Earth.
https://www.amazon.com/Chilling-Stars-New-Theory-Climate/dp/1840468661