Congaree National Park, South Carolinasynchronous fireflies
Out of season: the next synchronous fireflies season is in 2027.
Right now in Congaree National Park · September
- Paddling on Cedar Creek · Sep–Nov
225days to the next synchronous fireflies seasonusually May 11–Jun 20
Next 7 days
No frost, strong wind or heavy rain in the forecast.
National Weather Service forecast, issued Mon 2:21 PM (Eastern). Frost: a low of 36°F or less; wind: 20 mph or more; rain: 60% chance or more.
The park's viewing nights, past years
Congaree National Park opens for a few nights each year around the peak it predicts. Here are those nights, season by season, as the park announced them.
Bars are the nights each park opened for viewing, announced weeks ahead as its predicted peak (not an observed peak). Empty rows: no announcement on the park's website.
Sources (7)
- National Park Service, Congaree fireflies festival canceled, 2020 news release ↗ (opens in a new tab)
- National Park Service, Congaree firefly viewing, 2021 news release ↗ (opens in a new tab)
- National Park Service, Congaree firefly viewing event, 2022 news release ↗ (opens in a new tab)
- National Park Service, Congaree synchronous fireflies viewing dates, 2023 news release ↗ (opens in a new tab)
- National Park Service, Congaree synchronized fireflies viewing event, 2024 news release ↗ (opens in a new tab)
- National Park Service, Congaree firefly viewing event, 2025 news release ↗ (opens in a new tab)
- National Park Service, Congaree fireflies ↗ (opens in a new tab)
Congaree National Park through the year
- One of the best times to visitMar–May
- Synchronous fireflies (about two weeks)May–Jun
- Visitor center, boardwalk and front-country trails close at 4:30 p.m. on firefly nightsMay
- Hottest monthsJun–Aug
- Paddling on Cedar CreekNowSep–Nov
Where to see it: Firefly Trail. The designated trail for event nights; stay on it.
How we know
National Weather Service forecast and alerts (opens in a new tab) (Sep 28) · National Park Service, Congaree fireflies (opens in a new tab) (Sep 27) · National Park Service, synchronous firefly research at Congaree (opens in a new tab) (Sep 27) · National Park Service, Congaree firefly viewing, 2021 news release (opens in a new tab) (Sep 27) · National Park Service, Congaree firefly viewing event, 2022 news release (opens in a new tab) (Sep 27) · National Park Service, Congaree synchronous fireflies viewing dates, 2023 news release (opens in a new tab) (Sep 27) · National Park Service, Congaree synchronized fireflies viewing event, 2024 news release (opens in a new tab) (Sep 27) · National Park Service, Congaree firefly viewing event, 2025 news release (opens in a new tab) (Sep 27) · National Park Service, Congaree weather and seasons (opens in a new tab) (Sep 27)
Questions people ask
When are the synchronous fireflies at Congaree National Park in 2027?
There's no forecast yet. In a typical year it peaks May 11–Jun 20. The park announces its viewing nights each spring, and we add them here when it does.
Are the fireflies flashing at Congaree National Park right now?
Not now: the synchronous fireflies season is over for this year. The next one starts in about 225 days (usually May 11–Jun 20).
How do I get a pass, and what does it cost?
Passes come by lottery on Recreation.gov, one entry per household, in early April. It's $1 to enter and $24 more if you win, $25 in all. In 2026 there were 145 passes a night, each for one car with up to 8 people; RVs, trailers, big vans and buses aren't admitted.Source: National Park Service, Congaree fireflies ↗ (opens in a new tab)
What time is best?
Just after dark, usually between 9 and 10 p.m. In 2026 the gates let pass holders in from 7 to 8:30 p.m.Source: National Park Service, Congaree fireflies ↗ (opens in a new tab)
What are the rules on event nights?
Red lights only, kept low and pointed at the ground; no phones for light, photos or video; no pets (service animals are welcome); stay on the Firefly Trail; don't catch or disturb the fireflies; put insect repellent on before you arrive.Source: National Park Service, Congaree fireflies ↗ (opens in a new tab)
Does the weather matter?
Yes: thunderstorms are common in firefly season, and rain can slow or stop the flashing for the night.Source: National Park Service, Congaree fireflies ↗ (opens in a new tab)
Is it mid-May or June?
The park's pages say about two weeks between mid-May and early June (research page) or mid-June (event page). Its viewing nights have fallen between May 13 and May 29 every year since 2021.Sources: National Park Service, Congaree fireflies ↗ (opens in a new tab), National Park Service, synchronous firefly research at Congaree ↗ (opens in a new tab), National Park Service, Congaree firefly viewing, 2021 news release ↗ (opens in a new tab), National Park Service, Congaree firefly viewing event, 2022 news release ↗ (opens in a new tab), National Park Service, Congaree synchronous fireflies viewing dates, 2023 news release ↗ (opens in a new tab), National Park Service, Congaree synchronized fireflies viewing event, 2024 news release ↗ (opens in a new tab), National Park Service, Congaree firefly viewing event, 2025 news release ↗ (opens in a new tab)
Where are the best spots in Congaree National Park?
Firefly Trail: the designated trail for event nights; stay on it.
Are there closures or permits to know about in Congaree National Park?
Visitor center, boardwalk and front-country trails close at 4:30 p.m. on firefly nights (May).
What is Congaree National Park like through the year?
One of the best times to visit (Mar–May), Synchronous fireflies (about two weeks) (May–Jun), Hottest months (Jun–Aug), Paddling on Cedar Creek (Sep–Nov) and Visitor center, boardwalk and front-country trails close at 4:30 p.m. on firefly nights (May).