According to data from Polymarket, bets on French weather on two April dates had reached approximately $1.4 million|@Polymarket|X
Meteo France, the country’s weather forecasting office, has filed a complaint with police after suspecting that weather sensors at Charles de Gaulle International Airport may have been tampered with to favor Polymarket bets.
The investigation was triggered after automated temperature readings spiked unexpectedly by 4 degrees Celsius on April 6 and 5 degrees Celsius on April 15 evenings. On the latter date, temperatures surged from 16.9 degrees Celsius to 21.9 degrees Celsius in just 12 minutes, despite a simultaneous plunge in humidity.
Authorities noted that these anomalies coincided with unusually high trading activity on Polymarket, a prediction market platform. Data shows that bets on French weather for those two dates reached around $1.4 million—more than twice the typical monthly volume.
In one case, a trader reportedly made over $21,000 by betting that 18 degrees Celsius would not be the day’s high temperature.
Meteorologists warn that tampering with weather readings poses severe safety risks. The sensors in airports provide critical data for pilots to determine fuel use, altitude calibration, and runway spacing.
A prediction market where traders bet on real-world outcomes, but in recent times, the contracts have given way to people trying to manipulate real-life scenarios to win their bets.
Just last month, an Israeli journalist said he faced death threats from strangers demanding he retract his story on a missile strike in Jerusalem. He noted millions of dollars in Polymarket bets hinged on the strike’s official confirmation.