Meteo France has filed a complaint after an automated temperature sensor at Paris-Charles de Gaulle recorded two unexpected 22°C spikes in April that matched winning bets on the prediction market Polymarket. The spikes—on April 6 and April 15—produced $14,000 and $20,000 payouts. The climate group Infoclimat flagged the anomalies and forum members speculated about deliberate heating; authorities have opened an investigation and the cause remains unconfirmed.
French Authorities Probe Suspected Tampering Of Paris Airport Weather Sensor After Polymarket Bets
The sun sets over the River Seine on a mild afternoon as viewed from the Pont Alexandre III bridge, with the Eiffel Tower in the background, in Paris on March 9, 2026. - Abdul Saboor/Reuters
Paris — France's national weather agency, Meteo France, has filed a formal complaint after unusual temperature readings from an automated sensor at Paris-Charles de Gaulle Airport coincided with winning wagers on the prediction market Polymarket.
What Happened
On two separate days in April, the temperature sensor at Charles de Gaulle registered unexpected spikes to 22°C (about 71.6°F). The first occurred on April 6, when the sensor briefly recorded 22°C in the evening before readings returned to typical spring levels. A Polymarket bettor later collected $14,000 after successfully predicting the 22°C high. Nine days later, on April 15, the same sensor again registered 22°C, producing a $20,000 payout to another successful Polymarket wager.
Flags and Speculation
The French climate nonprofit Infoclimat flagged both anomalies; contributors on its forum speculated that the sensor may have been deliberately heated, with some suggesting a battery-powered device such as a hairdryer could have been used. Meteo France says the spikes were anomalous and that the precise cause has not yet been confirmed.
Investigation Underway
Meteo France told reporters it filed a complaint alleging the "tampering of an automated data processing system" and reported the matter to airport police at Charles de Gaulle. Authorities have opened an investigation; airport police declined to comment to reporters. Polymarket has been contacted for comment.
Polymarket, launched in 2020, allows users to bet on future events such as daily high temperatures for cities. The platform has faced prior scrutiny after a CNN investigation found a trader earned nearly $1 million by placing accurate bets on geopolitical events, raising questions about possible insider information.
Current Status
The investigation aims to determine whether the sensor data were deliberately manipulated. Meteo France and independent observers continue to analyze the station’s records and procedures; no suspect has been publicly identified and no definitive cause has been released.
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