The Latest Prediction Market Trading Scandal Involves the Weather, a Hairdryer, and Paris’ Charles de Gaulle Airport
Posted on: April 24, 2026, 11:17h.
Last updated on: April 24, 2026, 11:17h.
- French authorities are probing whether a weather station in Paris was tampered with
- Temperatures briefly soared on April 15 at Charles de Gaulle Airport during the evening hours
- Two traders reportedly profited over $35,000 on the temperature spike
Another day, another report of insider trading involving prediction markets. But this tale might be the most extraordinary yet.
The national weather service of France, Météo-France, has confirmed that it’s examining whether one of its monitoring stations that gathers weather-sensor data was recently compromised for the benefit of traders on Polymarket.
On April 15, a trader on Polymarket’s international platform profited more than $21,000 on trades of less than $120 that the day’s high temperature would reach 22 degrees Celsius (71.6 degrees Fahrenheit).
The trades were made in the evening hours, long after temperatures peaked at 18 degrees (64.4 degrees Fahrenheit) in the afternoon. As temperatures cooled during the evening, the temperature reading at the Charles de Gaulle Airport weather station in Paris suddenly jumped to 22 degrees.
The high temperature reading occurred at 9:30 pm local time. An hour earlier, the temperature read 16 degrees.
Was the Temperature Manipulated?
The temperature spike experienced at the Paris airport on April 15 at 9:30 pm didn’t last long. The 22-degree reading quickly regressed, cooling back down to 16 degrees about 30 minutes later.
The anomaly raised eyebrows within Météo-France.
The Polymarket account, “xX25Xx,” was behind the cheap, long-shot trades that the day’s high would not be 18 degrees. The market at the time of the executed trades implied that the contract’s other traders thought there was a 99% chance that 18 degrees would be the high for the day.
The xX25Xx account profited over $21,000 on the abnormal temperature jump. The trader wasn’t alone. Another account, “Hoaqin,” made similar trades in the moments leading up to the temperature surge. That trader made almost $14,000 in profits.
Météo-France says after reviewing its Paris airport weather station, the agency filed a complaint with the police related to the possible tampering of an automated system. It’s suspected that someone with access to the weather station used a cordless hairdryer or other handheld heating device to warm the data sensors.
Polymarket Stays Quiet
New York-headquartered Polymarket operates globally in approximately 180 countries. In the US, it has a separate platform that’s federally regulated by the Commodity Futures Trading Commission (CFTC).
The suspicious trading activity on the Paris weather occurred on Polymarket’s non-US platform. A spokesperson for Polymarket declined to comment on the Charles de Gaulle Airport weather station scandal.
France is among several European nations that have banned Polymarket. The online prediction market platform is geo-blocked, but, of course, skilled computer users know how to use virtual private networks to circumvent such digital barriers.
Outside of the US, Polymarket’s international platform operates from Panama through a partnership with Adventure One QSS, Inc., a company that claims to be “building and researching the pioneering use cases for blockchain technology.” Polymarket is a largely crypto-based prediction market exchange.
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