Polymarket bets win $37K after Paris airport temperature spikes

Two accounts on Polymarket collected about $37,000 after two markets settled using automated temperature readings from the Charles de Gaulle Airport station. The markets resolved on April 6 and April 15 after the station briefly reported a rise above 21°C on April 6 and a spike to 22°C on April 15.

The April 6 market paid a winner more than $16,000. The April 15 market produced roughly $21,000 in proceeds for the successful position. Both markets used the highest temperature recorded at the Charles de Gaulle automated station to settle contracts.

Analysts at blockchain analytics tool Bubblemaps flagged the anomalies, noting the spikes did not appear on nearby stations. The firm reported one account bought NO shares on an 18°C outcome shortly before the April 15 spike and later exited the position with about $21,000 in proceeds. “That spike didn’t show on nearby stations,” Bubblemaps analysts wrote.

Meteorologist Ruben Hallali reviewed the readings for investigators and described the rapid temperature jumps as unlikely to be natural. “Such temperature variations seem very unlikely, especially on these two dates, and over such a short period,” he told investigators, adding someone familiar with sensor operation could have intervened on site to produce a brief rise sufficient to validate a bet.

Météo France filed a complaint with the Roissy Air Transport Gendarmerie Brigade reporting suspected tampering with the operation of its automated data processing systems. The complaint asks police to investigate whether the station’s measurements were manipulated or whether there was criminal interference on or near the instrument shelter that houses the sensors.

Polymarket and the traders involved have not publicly described how the trades were placed or whether the platform is cooperating with the French investigation.

Investigators are expected to review access logs, maintenance records for the weather station and any surveillance or physical access records at the airport site to determine whether the sensor data were altered deliberately or whether equipment malfunction explains the spikes.

Platforms that settle contracts on objective data such as weather readings rely on automated feeds and specific observation sites to resolve outcomes. When a single station’s reading determines a market outcome, an unexplained anomaly at that station can produce disproportionate payouts for traders who bet on that reading.

Authorities are continuing their inquiry.