While weather derivatives exist in traditional finance, betting on the exact daily high temperature of a specific city is still a somewhat niche and novelty topic for retail prediction markets.

April 6, 2026 - April 9, 2026, the price of 23°C steadily surged from 18.5c to 33c. The reason is that as the resolution date approaches, weather forecasting models have become more precise regarding the specific cooling range and precipitation on April 10, solidifying 23°C as the most likely high temperature. April 6, 2026 - April 7, 2026, the price of 23°C surged from 18.5c to 29c as short-term weather forecasts confirmed incoming rain and a cooling trend for April 10, highly favoring this moderate temperature range. April 6, 2026 - April 7, 2026, the price of 28°C plummeted from 13.5c to 2.4c, as approaching precipitation and cloud cover effectively ruled out the possibility of an anomalous heatwave.

Between April 6, 2026, and April 8, 2026, the price of '15°C' plummeted from 31c to 0.4c as expectations for a warm day completely dissipated. Between April 6, 2026, and April 8, 2026, the price of '14°C' dropped from 26.5c to 0.4c for the same reason. Between April 6, 2026, and April 8, 2026, the price of '13°C' crashed from 29.5c to 0.6c, mainly due to a significant downgrade in the expected temperature for April 10 in the weather forecasts. Between April 6, 2026, and April 8, 2026, the price of '6°C or below' surged from 8c to a high of 43.4c, before settling around 32.2c, driven by an incoming cold front that lowered the expected maximum temperature to 6°C or lower. Between April 6, 2026, and April 8, 2026, the prices of '7°C' and '8°C' also climbed from low single digits to around 30c and 25c respectively, reflecting the confirmation of the cooling trend.

April 6, 2026 - April 9, 2026, the price of '16°C or below' continuously surged from 41c to ~98c, while the price of '17°C' crashed from 29c to less than 1c, and higher temperature options like '21°C' and '22°C' plummeted from above 30c to near zero. This was driven by the approaching target date (April 10), which resulted in highly accurate and convergent weather forecasts explicitly showing a maximum temperature of only 13°C-14°C, completely ruling out the possibility of reaching 17°C or higher.

April 6, 2026 - April 8, 2026, the price of the '18°C or below' option surged from 40.5c to around 96.5c, as approaching weather forecasts increasingly confirmed that the maximum temperature would be between 14°C and 16°C, well below 18°C. April 6, 2026 - April 8, 2026, prices for most options '19°C' and above plummeted (e.g., '19°C' dropped from 22.5c to 1.25c, '20°C' from 18.5c to 1.1c) because weather forecasts eliminated the possibility of higher temperatures.

The title states 'Seoul', but the resolution criteria explicitly use data from the Incheon Intl Airport station (RKSI). Incheon airport is coastal and often records different temperatures than downtown Seoul, creating a significant title-rule discrepancy trap. Furthermore, it strictly relies on Wunderground's whole-degree Celsius data and ignores any post-finalization revisions.

Between April 9, 2026, and April 9, 2026, the price of '13°C' surged from 24c to 42c, while '12°C' plummeted from 49c to 23.5c. This was due to high-frequency weather updates shifting the expected temperature peak from 12°C to 13°C as resolution approaches. Between April 8, 2026, and April 9, 2026, the price of '12°C' surged from 20c to 35.5c (peaking at 49c), and '11°C' spiked from 11c to 32.5c (before falling). This was due to weather models narrowing the confidence interval for the daily high as the date approached, temporarily pinpointing 11-12°C as the most likely peak. Between April 6, 2026, and April 9, 2026, the price of '14°C' steadily declined from 26c to 9c (later rebounding to 14c), as updated forecasts temporarily ruled out the probability of temperatures exceeding 14°C. Between April 6, 2026, and April 7, 2026, the price of '17°C or higher' plummeted from 30c to 13c (and later 0.5c on Apr 9), as clearer weather forecasts reduced the likelihood of unusually high temperatures. Between April 6, 2026, and April 7, 2026, the price of '12°C' surged from 10.5c to 22c, driven by meteorological data indicating a much higher probability of the high falling in this range. Between April 6, 2026, and April 7, 2026, the price of '13°C' dropped from 26.5c to 16.5c before rebounding to 21.5c, reflecting fluctuations in forecast models across adjacent bins.