How often to cicadas come out? Here's when we'll see (and hear) Brood XIII, XIX in 2024

Some U.S. states will soon experience an event that last occurred when Thomas Jefferson was president – two broods of cicadas emerging from underground at the same time.

Brood XIII and Brood XIX have not appeared together since 1803 and won’t again until 2245. But many Americans might not be thinking of the rarity of the cicada co-emergence and instead are dreading the ceaseless high-pitched buzz of trillions of insects.

Here’s when the cicadas will emerge from underground dormancy in what's been dubbed "Cicadageddon 2024."

When do cicadas come out?

Expect to begin seeing cicadas in mid-May.

"Cicadageddon" will likely end in late June. If the weather is consistently warm and dry, the cicadas will finish mating sooner, which would mean a shorter season.

These cicada broods have been waiting for well over a decade to make their grand entrance. Female cicadas lay eggs in trees, which drop to the ground and burrow before emerging as adult cicadas that then lay millions of eggs and die. Cicadas die after spending about five weeks above ground, but some species live for only three to four weeks.

Once they’re here, you can expect to see the pests in the trees and on the ground. More notably, expect to hear them – a chorus of cicadas can reach 90 to 100 decibels, which is about as loud as a lawnmower, according to CicadaMania. 

How often do cicadas come out?

Cicadas have the longest life cycle of any insect. These broods wait 13 or 17 years to emerge.

Researchers aren’t certain why they spend this cycle underground, but many agree it’s likely to avoid predators. Coming to the surface all together gives the cicadas a certain safety-in-numbers protection. It’s also harder for predators to specialize in killing cicadas when they don't emerge for decades.

What will the cicadas sound like? Listen and learn with these graphics

What states will see cicadas?

Seventeen states will see Brood XIII and Brood XIX this year:

• Alabama

• Arkansas

• Georgia

• Illinois

• Indiana

• Iowa

• Kentucky

• Louisiana

• Michigan

• Mississippi

• Missouri

• North Carolina

• Oklahoma

• South Carolina

• Tennessee

• Wisconsin

• Virginia

Do cicadas bite: How to prepare for 'trillions' this summer

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Contributing: Janet Loehrke

This article originally appeared on USA TODAY: When do cicadas come out? Expect to see (and hear) them these dates.