If you think of live shows as the music industry’s last reliable cash crop, then summer is the time of harvest. Not only are there more performance spaces when outdoor venues are open, fans are also more likely to turn out on weeknights.  “Every day is kind of like a weekend during the summer. And parents are more apt to let kids go to a midweek show than they would during the school year, so that allows us to go to many more cities than we would the rest of the year,” says David Zedeck, head of global talent and artist development for concert promotion giant Live Nation LYV 0.17 % , behind more than 60 tours this summer by acts from alt-J to the Zac Brown Band.  Years after the evaporation of recording revenues compelled more bands to hit the road and tour more frequently, the live-music landscape is shifting again, thanks to a boom in the number of music festivals in North America. Festivals offer musicians built-in audiences (and often heftier paychecks). And with more festivals around the country to hop among, acts have less incentive to mount their own headlining concert tours. That is contributing to a drop in the volume of tickets sold to concert tours. In 2014, there were 38.2 million tickets sold for the top 100 North American tours, down 4.7% from the year before, according to Pollstar. Gross ticket sales for these tours was $2.7 billion, down 2.2% from 2013.  A handful of contemporary acts have the drawing power to play stadiums this summer, including Taylor Swift, One Direction and Luke Bryan. Below that superstar tier, however, the most reliable sellers are “legacy” acts such as AC/DC, the Rolling Stones and Billy Joel, proving once again that nostalgia is one of the concert industry’s biggest assets. For the 50-year-old Grateful Dead, a scarcity of shows (five only) has led to a feeding frenzy on the ticket reselling site StubHub. “The stats around the Grateful Dead reunion blow everything else out of the water, in terms of an average cost, per-day basis,” says Glenn Lehrman, StubHub’s global head of communications.  Below a selection of the season’s most notable tours.  May 20 - Dec. 12  Since releasing her chart-topping fifth album “1989” last October, Taylor Swift’s live performances of the material have largely been relegated to award shows. That changes as she takes her new, pop-oriented songs on the road for a trek that includes arenas and stadiums across North America. Rounding out her bills are a who’s who of up-and-coming radio-friendly artists such as Vance Joy, Shawn Mendes, Haim, and James Bay.  June 7 - June 28  Last December, R&B musician D’Angelo surprised fans by releasing his long-awaited third album, “Black Messiah,” with no marketing or advanced warning. And live performances have been scarce as he’s only played two proper shows in the U.S., including a gig at New York’s Apollo Theater that sold out in just over an hour. Finally, fans will get a chance to catch him and his live band “the Vanguard” with a three-week tour of small theaters and clubs.  May 24 - July 15  For the Rolling Stones’s “ZIP Code” tour, the British-rock band is playing stadiums in such places as Columbus, Ohio, and Buffalo, New York, markets they missed during 2013’s “50 & Counting” tour. The 15-date run coincides with a deluxe reissue of their 1971 classic album “Sticky Fingers” (the band played all the songs on the album at a small club show last week in Los Angeles). They are promising to dig into some deep cuts for their stadium sets, too. “We move through different eras, and have such a huge back catalog, that every day a surprise comes up,” guitarist Ronnie Wood said in a recent Twitter Q&A of the band’s rehearsals.  The last time country star Shania Twain toured North America, George W. Bush was in his first term as President and Netflix was a simple startup that mailed you DVDs using the U.S. Postal Service. Eleven years later, after hunkering down in Las Vegas from 2012 to 2014 for an extended residency, she’s ready to get out on the road once more but promises this is the last time she’ll tour. “It’s an entirely different show from what we did in Vegas,” Ms. Twain said. “I’m going back into what’s more comfortable to me, the rock setting.”  Ireland’s biggest rock stars have had a tough stretch, starting with their controversial partnership with Apple last September that put their new album, “Songs of Innocence,” in everyone’s iTunes automatically. Then a freak bicycle accident forced Bono to undergo extensive rehabilitation. The band recently launched the “Innocence + Experience” tour, forgoing the stadiums of their previous tour for the relatively smaller setting of sports arenas. Live Nation’s Arthur Fogel, who has been the band’s promoter since 1997, says the tour is virtually sold out, which is “vindicating” after the backlash to the band’s album release. He says, “It was frustrating to see some of the body blows they were taking, and to know in my mind that we just had to be patient” for the band to prove itself on tour.  July 21 - Aug. 12  Brit singer Charli XCX and Bleachers frontman Jack Antonoff are probably best known for music they’ve made with other acts: She supplied vocal hooks on hits such as Iggy Azalea’s “Fancy,” and he is a member of the band fun. and helped produce Taylor Swift’s latest album. But as solo acts they have loyal fans and a maverick approach to pop music. All this helps make them a good match for a co-headlining tour, says Mr. Antonoff: “We have similarities, in the sense that we both exist on the outskirts of the pop world. Neither of us are really married to a certain scene or specific movement. But on the other hand, our music is also totally different.”  After selling out two nights at Yankees Stadium last year, Bronx native Romeo Santos, the top practitioner of the seductive “bachata” style of music, is taking a victory lap this summer. He was recently named Billboard’s Latin artist of the year, an award based on chart performance. Santos will conclude the latest leg of a world tour with another hometown run—three concerts at the Barclays Center arena in Brooklyn.  June 5 - Oct. 31  The term “boy band” doesn’t do justice to their big business: Last year, One Direction had the world’s top tour, selling 3.4 million tickets for a gross of $282.2 million, according to Pollstar. And with another string of stadium gigs on their summer schedule (and a new album in the works) the pop force could outdo itself this year, despite the loss of original member Zayn Malik, who quit the group in March.  May 28 - Oct. 17  Led by Brian Kelley and Tyler Hubbard, this country band came up opening for stadium acts such as Jason Aldean and is now on a hot streak as a headlining act—a reminder of how effective it can be to hitch emerging artists to superstars on tour, and to put out hit songs, of course. Singles such as “This Is How We Roll,” a celebration of cruising and partying that name-drops royalty of country (Hank) and rap (Drake), made Florida Georgia Line ever present on radio and at country-music awards shows. But the band hasn’t completely outgrown their days as a support act. They’ll open for Luke Bryan (featured on “This Is How We Roll”) at a handful of his stadium concerts this summer.  June 27 - 28, July 3 - 5  For its 50th anniversary, the long-lived jam band plays five concerts (billed as the band’s last), culminating with a three-night run at Chicago’s Soldier Field, the last venue at which the Dead performed before Jerry Garcia died, in 1995. For the many Deadheads who got shut out of the ticket sale, the band is offering remote viewing options, including live pay-per-view feeds, online streams and simulcasts in movie theaters. Controversy dogged aspects of the gigs, including the choice of Phish guitarist and singer Trey Anastasio to join the group on stage. Dead rhythm guitarist and singer Bob Weir says of the Phish member, “He’s going to have a lot to offer. He’s not going to be parroting Jerry, because there’s no point in that. At the same time he’s going to try and ring those lofty bells that Jerry was able to ring, and I’m sure he’s going to reach some of them.”  Corrections & Amplifications: Florida Georgia Line’s summer 2015 tour is not the band’s first headlining tour. An earlier version of this article incorrectly stated that it was. The U2 tour runs through November 15, not July 31.  Write to Mike Ayers at Mike.Ayers@dowjones.com and John Jurgensen at john.jurgensen@wsj.com
A roundup of summer concert tours, from Taylor Swift to the Grateful Dead. As the rise in music festivals eats into the number of tours by single acts, only the strongest like D’Angelo, the Rolling Stones, U2 and One Direction, survive.