The Great Smoky Mountains National Park is gearing up for its annual synchronous fireflies event—the largest gathering of synchronous fireflies in the Western Hemisphere. During the annual phenomenon, swarms of lightning bugs will light up the park at night. The incredible flashing display is so popular that a lottery system has been established for obtaining the coveted parking passes required to attend.
How to see the Great Smoky Mountains synchronous fireflies
In 2023, the lottery to see the synchronous fireflies in the Great Smoky Mountains National Park opens on April 28, at 10 a.m. EST, and will close on May 1, 2023, at 8 p.m. EST. Those interested in seeing the annual display can enter the lottery at Recreation.gov, and will be charged a $1 lottery application fee.
The 2023 viewing dates for the Great Smoky Mountain synchronous fireflies will be June 4 to June 11, 2023.
On May 11, 2023, all lottery applicants will be notified about whether their application was accepted or turned down.
Lottery winners will automatically obtain (and be charged for) the vehicle pass necessary to access the viewing area. The Great Smoky Mountains National Park will be handing out a total of 800 vehicle passes for the eight-day event (100 per day). Lottery winners will be charged $24 per vehicle and can bring a maximum of seven passengers in their car.
Each pass is valid only for a specified date, and an arrival time between 6:00 p.m. and 8:00 p.m. will be assigned. No additional passes beyond those assigned during the lottery will be made available.
Attendees will be asked to cover their flashlights with red or blue cellophane so that they don’t disrupt the viewing experience and to turn them off altogether when they have found a viewing spot. They will also need to stay on designated trails or paved surfaces at all times, and to not catch the fireflies (so leave those Ball jars at home, folks).
After visitors check in, parking attendants will direct vehicles into designated parking areas, where visitors can then leave their cars during the viewing. A designated number of ADA parking spaces will be available on a first-come, first-served basis. Primary viewing areas are Jakes Creek and Little River trails.
The firefly display takes place in the Elkmont section of the Great Smoky Mountains National Park.
Photo by William Silver/Shutterstock
What are synchronous fireflies?
Synchronous fireflies are a unique species of firefly (which is a type of beetle also known as a lightning bug) that can actually synchronize their flashing light displays. Their light patterns, which are produced in their “lanterns” along their abdomens, are part of a mating ritual that helps males and females recognize each other. The males will fly and flash their light and the typically stationary females will respond with a flash, according to the Great Smoky Mountains National Park’s dedicated synchronous fireflies page.
No one is exactly sure why the fireflies flash their lights in unison, and they don’t always do so. When they do, a burst of light ends with an abrupt period of darkness.
Fireflies’ bioluminescent lanterns are tucked into their abdomens.
Photo by Suzanne Tucker/Shutterstock
The peak mating season lasts for approximately two weeks each year, and the dates of the display vary from one year to the next. Scientists predict the dates based on factors such as temperature and the moisture in the soil. Even during the peak season, attendees aren’t guaranteed a perfect display, the park has cautioned. Environmental factors such as rainfall or cooler temperatures that fall below 50 degrees can shut down the display on any given night.
Other places to see synchronous fireflies
While the Great Smoky Mountains may have one of the most well-known firefly displays, there are other U.S. parks that also welcome synchronous fireflies each year. (Unfortunately, the lottery has closed for both of the following annual events, but those who are interested should mark their calendars for 2024—organizers are starting and ending the lottery application periods earlier in the calendar year compared to previous years.)
Congaree National Park
This year’s annual synchronous firefly viewing event at Congaree National Park will take place from May 13 to 16 and May 19 to 24. Similarly to Great Smoky Mountains, visitors need to win parking passes via a lottery system to attend. The lottery opened on April 6 and closed on April 12. Winners were notified on April 17. Parking passes cost $24 per vehicle for this event.
Allegheny National Forest
There are 15 species of firefly in Pennsylvania, and June is prime time to see them. The PA Firefly Festival takes place annually in Tionesta and is scheduled for Friday, June 30, and Saturday, July 1, in 2023. Registration for the lottery for the event closed on March 31.
This article originally appeared online in April 2019; it was most recently updated on April 21, 2023, to include current information.
