Impact of variations in solar activity on hydrological decadal patterns in northern Italy, D. Zanchettin et al., 06/2008, Journal of Geophysical Research, Volume 113, Issue D12 (notrickszone.com)
Over the 11 - yr solar cycle and the long term variations in solar activity, these variations correspond to typically a 10 % change in this ionization rate. (sciencebits.com)
Variations in solar activity also seem to affect global weather. (discovermagazine.com)