It has always been a mystery why Summer Sonic is not held in the relative cool of June or July, but at the very height of summer, when the August sun beats down upon the festival’s outdoor stages or typhoons power through the country, threatening disruption and cancellations to the event’s packed schedule.

And yet, each year, countless music lovers descend upon the Tokyo and Osaka iterations of the three-day festival, which this year celebrated its 20th anniversary before a planned hiatus for the 2020 Tokyo Olympics.

Though actual celebrations of the anniversary were in short supply on the ground, this year’s lineup was a bumper one, with a plethora of stadium-filling acts on a roster with excellent depth, including international superstars Red Hot Chili Peppers, home favorites Sakanaction, kawaii-metal darlings Babymetal, pop-duo The Chainsmokers and B’z, the best-selling Japanese group in history.

It was the Friday shows that suffered the worst from Typhoon Krosa, with Tokyo’s Beach Stage being canceled due to winds whipping up the sand on the beach into blinding dust storms. For the rest of the weekend, the main difficulty was the heat — a number of attendees were seen fainting with heat-related ailments over the weekend. And with temperatures approaching 37 degrees celsius in the shade, a special mention must go to the sadist who printed this year’s Summer Sonic T-shirt on black.

Highlights of the festival included neo soul and jazz prodigy Robert Glasper’s collaboration with Yasiin Bey (the artist formerly known as Mos Def), which was notable as much for its relentless groove as its juxtaposition with heavy metal outfit Maximum the Hormone, which played to a packed out Marine Stage immediately before Glasper’s enviable quintet; this year’s lineup catered to everyone.

© SUMMER SONIC ALL COPYRIGHTS RESERVED

Approaching the end of their world tour and seemingly at an energetic peak, British band Foals gave an incredibly tight, mosh-worthy performance on the Sonic Stage, accompanied by a small army of botanists and stage hands to dress the stage in greenery — a nice touch for a smaller stage that doesn’t see so much in the way of set design. Not a household name in Japan, the band will have won a few converts ahead of the Oct. 18 release of its new album, “Everything Not Saved Will Be Lost — Part 2.”

Saturday night headliners Red Hot Chili Peppers packed out the Marine Stage, with all but the most hardcore fans of Babymetal, who played the Mountain Stage concurrently, in attendence (was anyone watching Catfish and the Bottlemen?).

Though the band’s rendition of “Under the Bridge” made it clear why the Chili Peppers still occupy headline slots at festivals around the globe (unprompted, the entire stadium was filled with waving phone lights), the concert as a whole felt tired, the last breath of a great band whose founding members are now approaching 60. It was a performance plagued with mistakes, not an issue during the band’s big hitters but all too obvious on the lesser-known songs, when the group wasn’t supported by the voices of the crowd.

That performance couldn’t be more in contrast with Midnight Sonic Saturday headliners and curators Sakanaction, which filled the Mountain Stage for a flawless gig. Sakanaction inspires a certain cultish fervor in its fans (I wouldn’t want to be there the day lead singer Ichiro Yamaguchi realizes his despotic potential) and it’s easy to understand why: The music is catchy, the group’s stage presence magnanimous and the show about as slick as they come. It’s J-pop that transcends language and genre and demands attention.

Sakanaction’s appearance on the bill was unfortunate for D.A.N., a younger band fast building a solid live reputation. During an extended pause between two songs with the lights turned down, about three-quarters of D.A.N.’s audience, most of whom were waiting to see Sakanaction, assumed the gig finished and promptly left for the Mountain Stage where Sakanaction was due to play 30 minutes later. When the lights came back on, the Rainbow Stage was near deserted, a shock to D.A.N., whose members will have hopefully taken notes for future shows.

One of the most bizarre spectacles of this year’s Summer Sonic was the appearance and performance of virtual popstar and YouTuber Kizuna Ai (AI, geddit?), who caused a minor security issue on Sunday as fans rushed the Rainbow Stage to try and catch a glimpse of dystopia manifest. After her show the virtual (and actual) star tormented many of the international artists with painful-to-watch interviews that can be seen on her/its/their (what is the correct pronoun for a singularity that’ll eventually rule the world?) YouTube channel.

Following on from the tech revolution of summer 2018, when both Fuji Rock and Summer Sonic decided to introduce live streaming, Summer Sonic broadcast much of this year’s festival on YouTube. Apart from a few overzealous crane-cam operators who seemed determined to take the scalps of as many audience members as possible, the streaming seemed to go without a hitch, though the festival courted Twitter backlash on Sunday afternoon after it cut short K-pop four-piece Blackpink.

Fans in a flap: Blackpink fans vented their ire on Twitter after streaming of the K-pop act’s set was cut short. | © SUMMER SONIC ALL COPYRIGHTS RESERVED

Later in the day, and to no apparent controversy, rising Texas rap collective Brockhampton launched a storming performance on the Mountain Stage, dressed in silver jumpsuits and dripping with sweat. Sunday also offered a good platform for other up-and-coming acts such as FKJ (a live looper actually worth watching) on the Beach Stage and J-rock outfit King Gnu.

After this year’s festival, there is little question that Summer Sonic is succeeding when it comes to its lineup, but the upcoming hiatus should give the event a chance to consider what its broader mission should be.

In the U.K., Glastonbury Festival was lauded this year for banning all single-use plastic bottles, having already decided to stop the use of plastic cutlery, plates and straws, seizing on an increased public consciousness about plastic waste and environmental concern. In Australia, Splendour in the Grass offers carbon offsetting to its guests when they buy their tickets, using the money to fund renewables projects in the country.

Many other festivals have taken similar steps, but Summer Sonic currently demonstrates little ambition for any other concern besides entertainment. With such a big platform and success ensured by a reputation strengthened by years of good music, it seems a waste for the festival not to think beyond the boundaries of the music and champion other causes.

Twenty years is an impressive run for any festival. The next 20 offers an important and necessary opportunity for Summer Sonic to challenge itself and its guests to do much more. After all, if it gets much hotter, the festival will be forced to make more drastic changes anyway.

In line with COVID-19 guidelines, the government is strongly requesting that residents and visitors exercise caution if they choose to visit bars, restaurants, music venues and other public spaces.