https://www.mdpi.com/2218-1997/9/9/387 is a fascinating paper. A number of periodicities in muon flux are detectable. A strong signal with a periodicity of 125 days is found, along with a diurnal variation and one which correlates well with the temperature of the Earth’s atmosphere. The global magnetic field of the Sun influences the muon intensity and shows up as a 27 day variation.
However, another variation of about 64 days appeared at two solar maxima (but not all of them). I find this surprising!