French police are investigating possible tampering with a weather monitoring device at Paris’s Charles de Gaulle airport, after a Polymarket trader made thousands of dollars due to unusual temperature rises.
Riccardo Milani/AFP via Getty Images
hide caption
toggle caption
Riccardo Milani/AFP via Getty Images
A hair dryer? a lighter? A lucky coincidence?
Authorities in France are investigating possible tampering with weather monitoring equipment at Paris’ Charles de Gaulle airport after an unusual rise in temperatures was recorded around the same time a Polymarket trader lost money.
An anonymous trader with the username “xX25Xx” has vetted analysts and fellow traders on Polymarket, where people can bet on things like city peak temperatures and other real-world events.
The trader bet $119 that the weather in Paris would reach as high as 64 degrees Fahrenheit on April 15, and weather enthusiasts noticed a sudden increase in temperatures that day. Due to the sudden increase in temperature, the trader made a profit of $21,398.
Polymarket trader’s bets before deleting your account. Accessed via Wayback Machine.
Polymarket/Screenshot by NPR
hide caption
toggle caption
Polymarket/Screenshot by NPR
When? Local meteorologists denied The temperature discrepancy occurred naturally, the Polymarket trader deleted his account.
The French weather service, Météo-France, said it had filed a complaint with airport police about possible tampering with its equipment, the French broadcaster said. BFM TV told.
Météo-France and airport police did not respond to NPR’s requests for comment.
While authorities in Paris are still investigating what happened, weather watchers and Polymarket traders on online forums have raised two possibilities as to how the temperatures could have been raised: a lighter or a battery-powered hairdryer.
Unusual weather increase compared to another weather sensor in Paris.
bubblemaps
hide caption
toggle caption
bubblemaps
“love it!” wrote a Discord user named Vince, who regularly trades on weather on PolyMarket. “I want one of those cordless hair dryers that connects to the weather station with a cord!”
Another user known as Sakuku on Discord quipped: “The good old ‘blowdryer’ scam with the heat setting at the publicly accessible weather monitoring station near the airport,” he wrote. “It’s a classic.”
One Analysis French analytics firm BubbleMaps found that no other weather station in the region recorded a rise in temperatures, and the bet won by Polymarket traders was 20 times larger than their normal bet.
Polymarket did not respond to a request for comment.
Prediction markets like PolyMarket and Kalashi allow people to bet on every aspect of modern life, from what words President Trump will speak to the timing of military strikes in Iran and the outcome of the election.
As the sites have exploded in popularity, stories have circulated of traders going to extraordinary lengths to profit, such as standing outside a Super Bowl stadium to record the length of the national anthem and browsing through the software code of a musician’s website to discover record sales announcements that are not yet public.
Several high-profile examples of questionable insider trading have also emerged, such as when a trader bet more than $500,000 on the ouster of Venezuelan President Nicolas Maduro and the timing of the announcement of an Iran ceasefire. Going further back, prediction market analysts have identified one trader who benefited significantly from having advance knowledge of the pardon granted to former President Biden in his final hours in office.
In the face of the abuse and manipulation of these prediction markets, lawmakers have taken a flurry of action to rein in the sites and dozens of states have launched lawsuits aimed at regulating the apps as gambling businesses.
Right now, the Commodity Futures Trading Commission oversees the industry, with the Trump administration taking a light-touch approach to companies that break norms.
French weather bets took place on Polymarket’s unregulated foreign exchange, which is accessible only by US traders with a virtual private network.
Polymarket’s shows website It no longer relies on Charles de Gaulle weather sensor data and is instead using data from a device at Paris-Le Bourget Airport to decide bets.
