Where I live they seem to come and go. Some years there’s literally zero, then a few years later there’ll be so many you almost don’t wanna go outside because they might get in your mouth. Although admittedly I haven’t seen the usual swarms lately either. It’s long overdue and yet they’re not here.
It’s a big change from when I was a kid, still living in this same area, but we had a consistent, manageable number of fireflies every year.