An espresso? Good luck, baby? I had help? What’s the song of summer 2024?

A few weekends ago I had the pleasure of introducing Chappell Roan to my friends’ parents.

It all started when I had a few bars of “Good Luck, Babe” stuck in my head and couldn’t stop humming it. Next thing I knew, we were all learning the “HOT TO GO” dance. And by the end of the weekend, we were sitting on their patio in upstate New York, listening to lyrics about “some kind of sexually explicit love story” like it was the most normal dinner party music in the world.

Now that I’m back home in Brooklyn, I have a new favorite reference: You can’t walk a block without hearing someone playing one of Charli XCX’s instant club classics (from her album Kid) — especially now that Kamala Harris’ presidential campaign has embraced the internet’s cheery moves linking her to Brat Summer.

And this is the perfect time to mention that for weeks earlier this year I worked non-stop (because I’m a singer). It’s me, “Espresso.”

These artists—Chappell Roan, Charli XCX, Sabrina Carpenter of “Espresso”—have dominated my playlists this summer. My friends play their songs at parties. My social media feeds are flooded with news and memes about them. They’re inescapable.

So they must all be in the running for the song of the summer of 2024, right? … Right?!

Wrong. Take a look at the top of the Billboard Songs of the Summer chart right now and you’ll see that the Top 10 is a mess. Post Malone and Morgan Wallen are at number one with their song “I Had Some Help,” a song I honestly don’t think I could hum for you even if I were asked. Someone I’ve literally never heard of, Tommy Richman, is at number four.

So what’s going on? How do these anonymous people beat out the biggest pop girls for the title of song of the summer? And if I barely recognize the most popular song in America right now, is there still a song of the summer?

In the absence of a consensus definition, it’s helpful to take a look at the history of the summer song. The concept goes back further than you might think: to the 19th century, when melodies circulated primarily via sheet music.

As Phil Edwards wrote for Vox a few years ago, sales were slow. It would take decades for early hits like 1826’s “The Old Oaken Bucket” to spread across the country.

By the turn of the next century, new technologies like radio helped popularize songs much more widely and quickly. But while songs could become popular in the summer, there was still no official song of the summer.

“It’s not like people were walking around in 1925 and saying, ‘Do you think this is the song of the summer this year?'” music critic and author David Hajdu told CNN. “But it was starting to happen.”

In 1958, Billboard released its first Hot 100 chart, with Domenico Modugno’s Italian ballad “Nel Blu di Pinto de Blu (Volaré)” at the top. It gave us a yardstick for defining the song of the summer, but it certainly didn’t invent the concept. For a while, the Hot 100 seemed to correctly identify the season’s most ubiquitous music: 1964, the Supremes’ “Where Did Our Love Go?”; 1976, Elton John and Kiki Dee’s “Don’t Go Breaking My Heart”; 1982, Survivor’s “Eye of the Tiger.”

But that changes when we enter the 2000s. The 2000s begin with songs so recognizable that we felt we didn’t even need to play them on our recent episode of Today, explained: “Crazy in Love.” “Umbrella.” “Call Me Maybe.” “Despacito.” In the 2020s, things are starting to get crazy: I don’t know about you, but DaBaby’s “Rockstar” certainly didn’t define 2020 for me. Last year, I didn’t even hear Morgan Wallen’s “Last Night,” a ghostwriter, so how could it have been the song of the summer?

You might be surprised to learn that music listening has changed since Billboard started naming summer hits. We now live in what scientists have tentatively begun to call the “streaming era,” where much of our listening happens on platforms like YouTube, Spotify, and Apple Music in addition to radio.

The shift reduced the ability of radio DJs and music industry executives to name hits, and shifted power to listeners, many of whom are influenced by Spotify’s personalized recommendation algorithms, which the company has prioritized since at least 2020.

Since Billboard’s Hot 100 chart takes streaming into account, musicologist and Pop lit Co-host Charlie Harding says the charts are now more accurate.

“In the era of mass media monoculture, we just weren’t as good at capturing the collective listening of people,” Harding said on Today, explained. “Sure, we might have been streaming the same thing, but we didn’t know what people were listening to on repeat on their stereos. Now we can count exactly what people are listening to on streaming services.”

The streaming era has allowed new types of artists to enter the charts organically, building fan communities through nontraditional avenues. Right now, Harding points out, the top of the charts reflects all sorts of different listening communities: a black country artist like Shaboozey, pop princess Sabrina Carpenter, Big Three rapper Kendrick Lamar, slow-burn alt-indie Hozier…

But listening to music is, to some extent, a zero-sum game. As we’ve been knocking on the door of our listening niche, the biggest artists have also started to see their streams decline. All of this creates a world in which you might not recognize Billboard’s song of the summer.

But maybe it doesn’t matter.

“Whatever music your community listens to, that’s going to be your song of the summer,” Harding told us. “I think you shouldn’t care what everyone else is listening to. I think you should care about how your friends and your community are feeling.”

This story originally appeared in Today, explainedVox’s flagship daily newsletter. Register here for future editions.