Double Cicada Brood 2025. Brood xiii cicadas, mostly concentrated in illinois, iowa and wisconsin, come out of the ground every 17 years. Trillions of periodical cicadas will emerge from underground, shed their skins, and head for the trees, looking for love.
Their brood xix cousins emerge every 13. In 2025, two different groups—or broods—of cicadas will emerge at the same time.