Two Polymarket accounts have attracted suspicion after making $37,000 betting correctly on two unusual temperature readings of a weather station located in a major airport in France.

The two weather-focused prediction markets focused on the highest temperature in Paris on April 6 and 15, using the highest temperature recorded at the Charles de Gaulle Airport Station in degrees Celsius, according to Polymarket.

French media outlet BFMTV reported on Monday that the temperature suddenly climbed to over 21 degrees Celsius on April 6, before dropping again immediately. The market resolved with the winner taking over $16,000. The winning account is under 30 days old.

Meanwhile, blockchain analytics tool Bubblemaps reported a similar glitch for the April 15 market. The weather station showed 18 degrees Celsius most of the day, then suddenly spiked to 22 degrees Celsius before dropping back.

Some have questioned whether foul play was involved. Prediction markets are already facing growing scrutiny over insider trading and possible violations of gambling laws.