Just watching footage of the World Cup match from 32 years ago can make a person sweat.
The coaches squinted in the midday sun. The spectators, many of them wearing white in a feeble attempt to stay cool, fanned themselves frantically or stripped off their shirts even before kickoff. Just half an hour in, the players from Mexico and Ireland appeared drenched, slow and totally spent.
The day was June 24, 1994. The city was Orlando, Fla. The temperature on the field was at least 110 degrees Fahrenheit.
“People were passing out in the crowd,” recalled John Aldridge, a striker who scored Ireland’s only goal that day. “It was crazy.”
That match, held more than three decades ago, remains perhaps the hottest ever played in a World Cup tournament. Since then, the planet has warmed by about 1.3 degrees Fahrenheit and experienced more frequent episodes of extreme heat, raising significant concerns before the men’s tournament returned to North America this month for the first time since 1994.
All five matches played in Orlando that year — as well as several in other cities, including the final in Pasadena, Calif. — took place in incredibly hot weather.
This year, some matches have already been played on searing days, though not as hot as the Orlando match. Dallas is expected to see temperatures in the 90s on Wednesday, when Japan faces off against Sweden there; so is Guadalupe, Mexico, where South Africa will play South Korea.
The players who took part in the Mexico-Ireland match in 1994 look back on what they endured over those 90 minutes in disbelief. Mexico defeated Ireland 2-1 after the extreme heat and humidity hit the Irish especially hard.
“We Mexicans were in some ways more used to it than the Europeans,” Claudio Suárez, a Mexican center back on the 1994 team who is now with the broadcaster Fox Deportes, said in Spanish. “It helped us a little.”
More than a little, countered the Irish midfielder Ray Houghton, who is now with the broadcaster RTÉ Sport: “It looked like they were out for a Sunday stroll!” he said of the Mexican team.
Mr. Suárez recalled that the Irish “had desperation on their faces,” adding, “A few turned around to look at us like, ‘What is this?’”
In the stands, Irish fans were “pink and tender and panting,” the Irish Independent newspaper reported at the time. They flocked to a rain room — a spot inside the stadium where water sprayed down through pipes to provide attendees with some respite.
“As the game started a glorious cloud swept across the burning sun,” the Daily Mirror newspaper reported after the match. “It momentarily offered relief to players and fans, although the humidity still sucked the soul.”
Fans had been encouraged to arrive early, wear light colors and hats, and drink lots of water. More than 100 people fainted in the stands that day, several news reports said at the time, citing local authorities.
Kickoff was at 12:30 p.m., both to avoid Florida’s late afternoon summer thunderstorms and to allow fans in Europe to watch. But playing under those conditions was “ill-conceived,” Mr. Aldridge said.
The Irish team was used to playing a pressing game that required the athletes “to get in people’s faces,” he said, “and we struggled, because you couldn’t do that for 90 minutes. It was impossible.”
Staff members for the teams tossed plastic baggies full of water to players from the sidelines. The players then dropped the empty bags onto the field, leaving a mess, Mr. Aldridge, Mr. Houghton and Mr. Suárez recalled in separate interviews over the past few weeks.
In training sessions that week, players lost many pounds to the humidity, Mr. Houghton said. In matches, Mr. Aldridge recalled, he wore no sunscreen.
Much is different now. “They benefited from us being guinea pigs,” Mr. Aldridge said.
This year, FIFA introduced mandatory three-minute hydration breaks for players, one in each half of every match, despite some criticism that such breaks interrupt the flow of the game. Many stadiums now have roofs or shade coverings. And no match is being played in the Miami area before 6 p.m. (Sorry, European viewers.)
Miguel Herrera, who coached the Mexican team in the 2014 World Cup in Brazil, said that team doctors now measure players’ hydration levels for a few days before the match and give them fluids to be in top shape at kickoff. Teams also travel earlier to cities where they will be playing so that they can acclimatize, said Mr. Herrera, now with the broadcaster TelevisaUnivision.
Years after the 1994 World Cup, Mr. Suárez ran into Fernando Hierro, who had played in the tournament for Spain, and Carlo Ancelotti, who had been an assistant coach for Italy (and now coaches the Brazil squad). What did they discuss? How hot the first American World Cup had been, Mr. Suárez said.
“Hierro said, ‘It was so hot in Dallas,’” Mr. Suárez said. “Ancelotti said, ‘It was so hot in Washington.’ I said, ‘And none of you even had to play in Orlando!’”
Susan C. Beachy contributed research.
