It is openly being used by at least 8 states and explored by others, and several countries around the world.
Not saying it's causing the crazy rains we're seeing from tropical storms lately, as that has always happened to some degree. I do think seeding is happening more than is being admitted by the govt.
https://www.gao.gov/assets/gao-25-107328.pdf
https://www.scientificamerican.com/article/eight-states-are-seeding-clouds-to-overcome-megadrought/