As of today, out of season, returns ~May. Earth Exhibit tracks the live conditions and flags it the moment it is on.
Each May, select floodplain groves in Congaree National Park fill with synchronous fireflies (Photuris frontalis, the "snappy sync" species, not the Great Smoky Mountains' Photinus carolinus).
For about two weeks the males flash in near-unison along the boardwalks and levees, one of only a handful of mainland US sites for the behavior.
The National Park Service runs a lottery for the peak viewing nights in mid-to-late May.
Where to see it
A taste of where to see it. The full map, exact coordinates and the best timing for each spot live in the app.
| Viewing spots |
|---|
| Harry Hampton Visitor Center / Boardwalk Viewing Area |
| Cedar Creek / Bluff Trail Viewing Zone |
| + 1 more spot, with exact coordinates and timing, in the app → |
This is the short version
This page shows a taste. The app has the full list of where to see this, the exact timing, and live conditions for 1,000+ natural phenomena worldwide, so you know the moment one is genuinely worth the trip.