Every year synchronous fireflies put on a spectacle inside of the Great Smoky Mountain National Park. Here's How you can attempt to see it in person.

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Synchronous Fireflies Show

Every year fireflies put on an incredible spectacle inside the Great Smoky Mountains National Park.  So many people want to catch a glimpse of this natural light show, that the National Parks Service has to host a lottery for car passes into the park. So why are the synchronous fireflies putting on this spectacle?  Well, it turns out it has to do with their mating season.

Scientists studying the synchronous firefly have determined that the males flash in unison as a way for the female to be certain she is responding to one of her kind. There are other firefly species flashing at night, and some of them are predatory, so she must be able to recognize males of her species.

The flash pattern of Photinus carolinus is a series of 5-8 flashes, followed by a pause of about 8 seconds, and then this pattern is repeated. Initially the flashing appears random, but the period of darkness is synchronized. As more males start joining in, the flashing will also begin to synchronize and entire sections of the forest will be pulsating with light.

When Can You See the Synchronous Fireflies

This natural synchronized light show takes place every year for about 2-3 weeks in either May or June.  The National Parks Service evaluates the daily temperatures to try its best to estimate when this event will take place.  Since fireflies aren't on a set schedule, the National Parks Service works hard to try its best to pinpoint when the spectacle will begin.

How to See the Synchronous Fireflies

If you want to catch a glimpse of the synchronous fireflies, you'll need to join in on the firefly viewing lottery.  Due to the number of people who want to view the fireflies, the National Parks Service has had to implement a lottery for car passes, because supply simply cannot meet demand.

The window to enter the lottery for vehicle passes is  April 28th at 10 AM to May 1st at 8 PM.  On these days you can pay $1 to submit your application to the lottery.  On May 11th you will be notified if your application was accepted.

**Lottery winners will be charged a $1.00 application fee. Successful applicants will automatically be awarded parking passes and $24.00 will be charged to the same credit or debit card used for the application fee.(collected on Recreation.gov) to help cover the cost of viewing supplies and nightly personnel to manage the viewing opportunity near Elkmont Campground.

If you want to enter the lottery, you can do so starting April 28th through Recreation.Gov.