May 13, 2026 - May 14, 2026, the price of 62-63°F surged from 20c to 39c, and 64-65°F rose from 26.5c to 37c, as short-term weather forecasts for the resolution day became highly definitive, indicating the high would land within this range. May 12, 2026 - May 13, 2026: The price for 64-65°F rose from 21c to 33.5c before settling at 28c, while 60-61°F surged from 5.5c to 17.5c. This was caused by fine-tuning of weather models as the resolution date approaches, adjusting the expected high temperature lower due to anticipated rainfall and cooler conditions.

The title asks for the highest temperature in 'Seoul', but the rules explicitly specify using data from the 'Incheon Intl Airport Station (RKSI)'. Incheon Airport is located on an island, and its temperatures can differ significantly from central Seoul, creating a major trap for participants. Additionally, the rounding to whole degrees Celsius is a crucial detail.

May 13, 2026 - May 14, 2026, the price of the '26°C or higher' option surged from 26.5c to 58.5c because, as the date approaches, weather forecasts indicated a significant increase in temperature, sharply raising market expectations for high temperatures. May 13, 2026 - May 14, 2026, the price of the '22°C' option plummeted from 12.5c to 0.85c, and the '23°C' option plummeted from 17.5c to 3.7c, as upward revisions in forecasted temperatures led to a sharp decrease in the probability of lower temperature ranges.

There is a notable divergence. The National Weather Service (NWS) explicitly forecasts a high near 78°F for Chicago on May 15, and other outlets like AccuWeather also predict 74-75°F or higher. However, the prediction market only prices the '74°F or higher' option at 37.5%, reflecting a conservative market sentiment or information lag regarding the expected warming.