It's Almost Cicada Time! Help Radiolab Track #Swarmageddon : The Two-Way The once-every-17-years event begins when ground temperatures reach 64 degrees. This how-to will give you a heads up on the historic swarm.

It's Almost Cicada Time! Help Radiolab Track #Swarmageddon

A newly emerged adult cicada dries its wings on a tree in Washington, D.C. Alex Wong/Getty Images hide caption

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Alex Wong/Getty Images

A newly emerged adult cicada dries its wings on a tree in Washington, D.C.

Alex Wong/Getty Images

If history proves correct, Magicicada Brood II will emerge this spring after living underground for 17 years.

In many places along the Eastern Seaboard — from North Carolina to Connecticut — the cicadas will fill the skies, breed and then quickly die. National Geographic points out that historically, this group, known as Brood II, has been so prolific that picking up their carcasses can sometimes feel like raking leaves in the fall.

Pinpointing just when they will emerge is tricky. But we do know that they generally begin to emerge when the ground temperature — 8 inches from the surface — reaches 64 degrees.

That's where you come in. As All Tech Considered reported last month, our friends at Radiolab want to track the once-in-a-generation phenomenon and have put together instructions on how you can build your own sensor and submit your temperature information. With temperatures rising, now's the time to get going.

We spoke to John Keefe, WNYC's senior editor for data news, who confirmed that with about $80 in parts from RadioShack and two hours of work, you could make a temperature sensor that delivers information using nine LED lights. As the temperature changes, the combination of LED lights change. You then go to their site to decode what it's telling you.

A cicada warning system. Radio Lab hide caption

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Radio Lab

Once the sensor hits 64 degrees, you'll know what to expect and those in the south can warn those of us farther north of the impending #swarmageddon!

Radiolab's building instructions are here. John says if you're not that ambitious you can always just buy a soil thermometer (this one is $6.32) that will detect temperatures 8 inches underground.

If you're in New York, however, there's better news: Radiolab is hosting two events where you can make your own cool, LED light sensor with the Radiolab folks.

The events are:

-- 7:30 p.m. Monday, April 8 at Brooklyn Brewery in Williamsburg with Jad Abumrad and the Data News Team. (21 years or older.)

-- 12 p.m., 1 p.m. and 2 p.m. Sunday, April 14 at the New York Hall of Science in Queens. (Ages 12 and over.)

Radiolab put together this video, explaining the project:

Radiolab shows you how to make a ground temperature sensor.