Uncovering the Hair Dryer Scandal: How Heat Sensors Were Tampered With to Manipulate Weather Betting and Steal Thousands

French authorities have launched an investigation into allegations that a hair dryer was used to manipulate weather sensor data at Charles de Gaulle Airport in Paris, enabling fraudulent bets on a cryptocurrency-based prediction market. The probe was initiated by Météo-France, the national meteorological service, after abnormal temperature spikes were recorded at the airport on April 6. According to reports, the sensor registered a sudden 4°C increase within just 12 minutes, pushing the reading past 22°C — a significant deviation from expected conditions around 18°C at the time. One user reportedly placed aggressive bets on temperatures exceeding 21°C on the Polymarket platform and walked away with nearly €30,000 in winnings. A second anomaly observed on April 19 heightened suspicions of tampering, prompting investigators to examine whether the sensor had been physically interfered with. Euronews and The Guardian have reported that the heat may have been artificially increased using either a lighter or a hair dryer, with one Discord conversation reportedly capturing a user asking a peer: “What did you do to the temperature sensor at Paris airport yesterday? Was it a hair dryer or a lighter?” The incident has drawn attention to the vulnerability of real-world data feeds used by blockchain-based prediction markets. Polymarket, which allows users to bet on outcomes ranging from elections to weather, saw unusually high volumes on those days, with some reports indicating daily turnover exceeding $500,000 in related trades. Three different cryptocurrency wallets were linked to bets placed on April 15 forecasting a Paris temperature of 19°C, which collectively generated over $280,000 in profits when the temperature unexpectedly surged by 5°C later that evening. Météo-France confirmed it had referred the matter to French police after receiving concerns from weather enthusiasts who doubted the legitimacy of the data. The agency said it is assessing whether its national weather infrastructure is being targeted by individuals seeking to exploit prediction markets for financial gain. Although no arrests have been made and no official conclusions released, the case underscores growing concerns about the integrity of oracle-dependent systems in decentralized finance. As prediction markets expand beyond traditional domains like sports and politics into areas such as climate and public health, safeguarding the accuracy of external data inputs remains a critical challenge.