The 7 trends that defined the millennial summer of 2019

The rise of CBD took off last year, but it really peaked this summer. It's caught on everywhere from San Antonio to New York City and Los Angeles in the form of CBD lattes, CBD-infused donuts, and more.

An active ingredient in marijuana, CBD doesn't get you high. Millennials love it for the anxiety relief and calmness it's said to provide. But they're not the only ones — boomers are a fan too, according to Jean Ban of Supermarket News.

Even 75% of chefs named CBD and cannabis-infused food as a hot trend in 2019, reported Amelia Lucas for CNBC, citing a National Restaurant Association Survey. While the FDA has prohibited adding CBD to food and drinks, some restaurants are selling CBD-infused products to meet demand, she said.

Regulations surrounding CBD are a gray area, and local regulators have been cracking down on its use this summer, according to Lucas.

It's near impossible to go a day without spotting the leopard print midi skirt on the street — or during an Instagram scroll. Look no further than the parody Instagram account @leopardmidiskirt to see just how the silk bias-cut leopard print midi skirt has become a classic summer staple — particularly in New York City, as Jess Bergman points out in the Tweet below.

It's plenty versatile, having been paired with everything from vintage tees and leather jackets to sneakers. As Claire Valentine for Paper wrote, "Animal prints contain multitudes, from self-aware playfulness, self-serious sexiness or that renewed favorite, camp."

did every woman in manhattan wake up one morning and decide to buy a leopard-print midi skirt

— Jess Bergman (@jesslbergman) May 22, 2019

Technically released in American bookstores in the spring, "Normal People" by 28-year-old author Sally Rooney was such a hit that it was still being buzzed about by the time summer rolled around. It quickly became a book-club staple and was recently optioned into a Hulu series.

Kathryn Lyndsay of Refinery29 called carrying a Rooney book "a new Instagram status symbol."

In "Normal People," Rooney — who was lauded as "the first great millennial author" by The New York Times — explores the complexities of millennial romance and young adulthood in a subtle, genuine way by following the on-again, off-again relationship of Marianne and Connell.

Read more: I read the book everyone's talking about by the 28-year-old novelist being hailed 'the first great millennial author,' and I totally understand the hype

You could nary walk into a bar this summer without hearing the country-rap duo of Lil Nas X and Billy Ray Cyrus in your ear.

Lil Nas X's "Old Town Road" originally caught on when featured as the soundtrack to a compilation of video app Tik Tok's #YeeHawChallenge, eventually catching the attention of celebrities like Justin Bieber and Mark Ruffalo, according to Dan Jackson of Thrillist.

Lil Nas X then dropped a remix with Billy Ray Cyrus in May, reported J'na Jefferson of Vibe. In July, it tied the record for longest-running No. 1 hit on the Billboard 100 of all time, she said.

Millennials find it catchy and fun — unofficial requirements for every year's song of the summer.

Read more: Tech execs in $400 sneakers and Instagram influencers in $6,000 Louis Vuitton windbreakers: 5 ways wealthy millennials are turning to 'uniforms' to cement their identity and status

Who's having a hot girl summer? One social media scroll, and it's not hard to find the hashtag #hotgirlsummer.

You can thank Megan Thee Stallion for that — she started the trend with the first lyric of her song "Cash Shit" ("Real hot girl shit") and album cover art, explained Kathryn Lindsay of Refinery29. Since its release in late May, the catchphrase has been hashtagged on Instagram more than 511,000 times. It's also made many an appearance on Twitter.

Megan Thee Stallion told The Root of the phrase: "It's about women and men being unapologetically them, just having a good-ass time, hyping up their friends, doing you. You definitely have to be a person who can be the life of the party and just a bad bitch."

In August, she released an eponymous song to the catchphrase.

am I too late to #hotgirlsummer 🥵 pic.twitter.com/GlgmRJR4cK

— dudeSaradude (@__sararose__) August 25, 2019

Earlier this year, travel-planning site müvTravel named Lisbon the most popular travel destination for millennials in its Top 30 Millennial Travel Destinations for 2019 list, which analyzed the most popular bucket-list destinations of müvTravel's millennial users.

It was on to something. Photos of Lisbon, as well as other cities in Portugal, have been cropping up all over Instagram. The city has more than 8.5 million hashtags on Instagram to date.

Located on the coast, Lisbon is also in proximity to beaches and resort towns for a day trip — and millennials love it for its architecture and neighborhoods that charm by day and buzz at night.

Source: Lisbon is the hottest travel destination for millennials in 2019. We asked 20-somethings for their best travel tips — from fairy-tale castles to buzzing nightlife, here's what they said.