Why can’t F1 cars race in heavy rain? The reasons we rarely see full wet tyres
Heavy rain still stops grands prix, and F1’s 2026 cars have yet to show they’re any better in it. But that’s not necessarily Pirelli’s fault…
Sepang produced good racing, but made the headlines for other reasons
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Formula 1 returned to Sepang after nine years away and spent the first part of its Sunday afternoon looking as though it had forgotten how to go racing.
Torrential rain delayed the start, and then, when the cars finally left the pitlane, several of them slowed to a crawl on the way to the grid, and the start was abandoned.
Max Verstappen eventually won a race that ran hours behind schedule.
The result was important for Verstappen and Red Bull, but it mattered less than what the afternoon exposed: Three things Formula 1 used to have, and has let slip. That is, engines that work in all conditions, the willingness to race in the rain, and the sort of circuit that rewards a driver who tries something.
Sepang offered a reminder of each.
Complaints about the problems and complexity of the new power units are an old story by now, but Sepang highlighted new issues that brought them back into the spotlight and left drivers and fans confused and upset.
This time, unlike in some of the early races of the new rules era, the cars didn’t fail on the grid. They failed trying to get there, which is what made it so damning and embarrassing.
Verstappen was one of several drivers affected by the glitch
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Verstappen was the first to trigger the problem, and when he looked in his mirrors, he saw a pack of cars that couldn’t work out what was going on.
“It was like the Lego race,” he said, a reference to a toy-car event held at Silverstone before the British Grand Prix.
At one point, the cars were five-wide on the straight because nobody understood what was happening. Lewis Hamilton had to stop on track, shut the car down and restart it.
“I’ve never done that before,” he admitted.
The cause was a software bug. The FIA said an “unprecedented combination” of low engine speed, low-grip conditions, wet-weather energy management settings and the circuit’s sector configuration led to a loss of power for a number of cars.
Its single-seater director, Nikolas Tombazis, described cars going very slowly as a “concertina effect” between them, and a bug that stopped power being redeployed so they couldn’t start again.
The FIA also said the problem hadn’t been detected by it or the teams in testing, or during the laps to the grid.
“These engines are so complicated and a lot of software is implemented,” Verstappen said.
At low speed and low revs, the engine simply bogs down. “It was just like driving at, what, 35 kilometres, going uphill, actually losing speed,” he added.
Norris was one of several drivers who spoke against the engines
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Normally the car recovers in a second or two. This time it didn’t, for a lot of cars at once. The end result was a shambolic image in which the safety car, instead of leading the field, was stuck in the middle of it.
The fix was software as well. The FIA removed the energy limit in the affected sectors with an updated release sent to every team during the delay, and the delay itself was about loading it.
“Some had faster laptops than others,” Hamilton said. Verstappen joked that Red Bull’s partnership with Oracle meant it had a very fast connection.
“It’s just horrible,” world champion Lando Norris said. “It just proves that we shouldn’t have any of that stuff, the electronic side.”
Carlos Sainz again questioned how F1 has arrived at this situation (“Who decided five years ago that this was the direction to go?”) and said the sport needs to have a “hard look” at itself.
Sergio Perez labelled what had happened as “totally unacceptable”.
It would be unfair to blame the whole engine formula for one bug, and the FIA has promised a full review with the teams and manufacturers, but a power unit that can be stopped by a wet formation lap is exactly the failure a pinnacle series is supposed to design out.
“That’s not what you want for the sport,” Verstappen said. He was right.
The rain at Sepang was heavy, but it didn’t last. A 40-minute delay ensued as race direction waited for better conditions before it sent the cars out behind the safety car for several formation laps, but we still had the prospect of the first fully wet race for the 2026 cars.
By the time the race started, the track was mostly dry
Red Bull
But the software glitch put paid to that. The tech issues, the stoppages, and all the laps behind the safety car guaranteed the race would run on a drying track unless more showers hit the track later, something that didn’t happen and that left everybody still wondering what a wet race looks like with the 2026 cars.
Rain has given Formula 1 some of its best afternoons: Ayrton Senna’s opening lap at Donington in 1993, Olivier Panis winning at Monaco in 1996, and Hamilton passing Timo Glock on the last lap at Interlagos in 2008 to take his first title were all wet races.
Compare that with Spa in 2021, when the cars did a few laps behind the safety car and half points were awarded.
That is the version of rain modern Formula 1 has settled into: a risk to be managed rather than a test to be run.
Some of F1’s most memorable drives have been in the wet
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Sepang even showed what rain adds when the sport lets it. Only nine cars started on intermediates, while Hamilton, Charles Leclerc, Lando Norris and Oscar Piastri went for slicks.
The track took much longer than expected to dry, and a safety car on lap nine, caused by Valtteri Bottas’s Cadillac crash, brought the whole field into the pits.
Strategy became a gamble again, with real winners and losers. It was only a few laps’ worth, but it was a reminder of how much variety the weather gives a race.
Over the past years, Formula 1 has had a tendency to do as much as possible to avoid wet races, and the 2026 cars make this harder.
Energy deployment, recovery and software maps all assume a clean, predictable lap, and the wet is the least predictable thing a lap can throw at them, as the pre-race laps showed.
If rain is the condition the cars weren’t built for, one of the things that made Formula 1 worth watching has been engineered out.
The race at the front wasn’t the main story of the weekend, at least not in terms of action.
Verstappen took pole and the win quite comfortably despite the safety car removing his advantage, so the best racing was further back, which is what makes it a useful test of the track.
The action behind the leaders was intense for most of the race
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The majority of drivers were looking forward to be racing at Sepang: those who had never raced an F1 car before this weekend were excited to finally try it out, while those returning to the circuit were delighted to be back.
Sepang is not only physically demanding and a bit of a lottery when it comes to the weather but, with the 2026 cars, it enabled close racing that didn’t look artificial as drivers could follow each other closely and pull overtakes that didn’t lead to the endless yo-yo racing seen elsewhere.
Some of that racing was down to the conditions, and it’s fair to say so. Mixed tyres and a scrambled order will always produce passing, but it was the track that turned the jumbled order into overtakes.
Sepang is wide, with long straights and heavy braking zones, which gives drivers a choice of lines even in cars that are hard to follow.
Heavy rain still stops grands prix, and F1’s 2026 cars have yet to show they’re any better in it. But that’s not necessarily Pirelli’s fault…
Compare that with the street circuits Formula 1 keeps adding: Madring, Miami and Las Vegas cost enormous amounts to stage, and they spend that money on spectacle while the track itself narrows the options.
Sepang was a good reminder that F1 would do well to change direction and choose its venues carefully in order to produce a better on-track spectacle that is enjoyable to watch without having to build new circuits in the middle of busy cities.
In the end, Formula 1 left Sepang with plenty to learn from the weekend: The engines have to work in the conditions the sport races in; the races have to be run in the rain instead of being waited out; and the people in charge should remember what a good circuit looks like.
One afternoon in Malaysia was enough to remind everybody of all that.