The title mentions Seoul, but the resolution rules explicitly specify the Incheon Intl Airport Station. Incheon is coastal and its temperatures often differ noticeably from central Seoul, posing a trap for traders who only read the title. Additionally, the resolution uses whole degrees Celsius, adding a layer of precision risk.

April 16, 2026 - April 17, 2026, the price of the '21°C or higher' option surged from 26c to a peak of 81c (currently settling around 80c). This was driven by unseasonably warm weekend weather warnings from the Korea Meteorological Administration, forecasting early-summer-like temperatures (reaching 21-23°C in Incheon) which drastically shifted market expectations for Incheon Airport. April 16, 2026 - April 17, 2026, prices for lower temperature options such as '15°C', '16°C', and '17°C' plummeted (e.g., 17°C dropped from 18.5c to around 1c), also as a direct result of the updated heatwave forecasts pricing out the likelihood of cooler temperatures.

April 16, 2026 - April 17, 2026, the price of '31°C' surged from 22c to 37.5c, and '30°C' temporarily spiked from 20c to 40c. Meanwhile, '28°C or below' plummeted from 26.5c to 5.5c. This occurred because, as the target date approached, updated meteorological models ruled out lower temperature extremes and revised the expected high upward into the 30-31°C range.

While checking the weather is a daily habit, predicting the exact high temperature at a specific airport on a random date is a niche and arbitrary topic that average people wouldn't naturally ponder.