According to a recent study published in Eos, researchers mining data from the National Lightning Detection Network found a 32% decrease in lightning counts across the Lower 48 states in May and June 2020 compared with previous years. The researchers are not sure why this decrease was so high but suggest it may be linked to the presence of persistent high pressure over parts of the US and could even be linked to the pandemic, which caused the shutdown of some manufacturing plants and less driving, resulting in less pollution and aerosols in the air. This in turn could lead to fewer thunderstorms and associated lightning. Other lightning detection networks saw less of a change but did not look specifically at the US. You can read more here.