A disparate set of tropospheric variations correlated with several types of space weather variations can be understood in terms of responses of the current density Jz in the global electric circuit to space weather inputs, and then responses of clouds to changes in Jz. Brief reviews will be given of the global circuit and its responses to space weather; of charging of clouds by Jz; and of proposed mechanisms for effects of charge on cloud microphysics. For stratus-type clouds with cold tops electroscavenging is likely to increase contact ice nucleation and drizzle production, that may affect cloud lifetime and cloud cover. For clouds in general, electroscavenging affects cloud processing of aerosol particles, and may change CCN concentrations and the indirect aerosol effect. The production of ultrafine aerosol particles and their growth and processing near clouds are also likely to be affected by changes in both atmospheric ionization and by Jz.