Between May 2, 2026, and May 4, 2026, the price of the '74°F or higher' option surged from 77c to 98c. This was due to weather forecasts becoming highly certain of a warm day as the date approached, eliminating market doubts about lower temperature ranges.

The title asks for the temperature in Seoul, but the rules strictly specify the Incheon Intl Airport Station as the resolution source. Incheon's coastal climate can cause its temperature to differ from downtown Seoul. Additionally, resolution relies on whole-degree Celsius data strictly from Wunderground, so participants must be careful regarding the location mismatch and rounding rules.

May 3, 2026 - May 4, 2026, the price of the 18°C option surged from 32c to nearly 99c, while options for 19°C and higher plummeted to near zero. This is because the afternoon in Korea has passed, and the daily high temperature data has essentially been finalized at 18°C. May 2, 2026 - May 3, 2026, the price of the 17°C option rose from 26c to 41c, and the 16°C option dropped from 28.5c to 10c, as the latest weather forecasts heading into the resolution day revised the expected high temperatures slightly upwards towards the 17-19°C range.

May 1, 2026 - May 2, 2026: The price of claude-opus-4-6-thinking surged from 73c to 94c, driven by its sustained dominance on the LMSYS Chatbot Arena leaderboard and increasing market confidence as the resolution date approaches. Concurrently, other competing models (e.g., claude-opus-4-7-thinking, gemini-3.1-pro-preview) saw their prices plummet by more than 10c down to near 1c, reflecting their fading chances of taking the top spot.

Predicting the daily high temperature in a specific city falls under weather prediction markets. While not uncommon in professional trading (weather derivatives), it is quite niche for the general public. Few people actively track or bet on such specific meteorological metrics unless they live locally, giving it a moderate novelty factor.