The title mentions 'Seoul,' but the rules explicitly state the resolution source is the Incheon Intl Airport Station. Given the geographical distance, temperature differences may occur. Users relying solely on downtown Seoul's weather data might be misled. Additionally, data resolves only to whole degrees Celsius.

April 11, 2026 - April 12, 2026, as weather forecasts became clearer, the prices of the '20°C' and '21°C' options climbed from around 15c and 11.5c to peaks of 28.5c and 29c respectively, reflecting increased market confidence in these temperature ranges. April 9, 2026 - April 12, 2026, as meteorological models reached a consensus on a 20-21°C maximum for Incheon Airport (RKSI), extreme high-temperature options plummeted. '23°C or higher' crashed from 38.5c on the night of April 9 to around 8.7c; meanwhile, '20°C' and '21°C' experienced wide two-way swings before steadily rebounding to near 30c. April 9, 2026, divergent forecasts regarding high-pressure systems and sea breeze impacts initially caused '23°C or higher' to surge from 8.5c to 38.5c.

Between 2026-04-11 and 2026-04-13, the price of 15°C plummeted from 35c to 7c, while the price of 13°C surged from 15c to 40.5c. This is because, as the resolution day arrived, updated weather radars and forecasts confirmed a cooler high temperature falling in the 13°C or 14°C range, eliminating the chance of 15°C. Between 2026-04-10 and 2026-04-11, the price for 14°C surged from 20.5c to 35.5c, while 15°C dropped from 35c to 23c. This was due to updated meteorological models slightly lowering the expected high to the 13-14°C range as the resolution date approaches. Between 2026-04-09 and 2026-04-10, the price for 13°C dropped from a peak of 28c to 11c, reflecting updated weather forecast models shifting away from cooler expectations. Similarly, the 12°C option fell from 20.5c to 2.25c, confirming the initial trend of warming forecasts before the recent adjustment.

2026-04-12 - 2026-04-12, the price of 25°C surged from 32c to 42c, as the latest forecasts lean towards a high of 25°C. 2026-04-12 - 2026-04-12, the price of 24°C surged from 25.5c to 36.5c then dropped back to 23.5c, due to meteorological models fluctuating between 24-25°C for the daily high. 2026-04-12 - 2026-04-12, the price of 23°C plummeted from 23c to 11.5c, because approaching settlement, forecasts show it's unlikely the high will be as low as 23°C. 2026-04-09 - 2026-04-11, the Yes price of the 22°C option dropped from 18c to 7.1c, as updated short-term weather forecasts further ruled out the possibility of lower temperatures, shifting the expected center toward 24-25°C. 2026-04-09 - 2026-04-10, the Yes price of the 26°C option plummeted from a high of 26c to 3.5c (later rebounding slightly to 11.3c on the 11th), because as the forecast date approaches, weather models ruled out the possibility of higher temperatures, shifting the expected high temperature center downwards. 2026-04-09 - 2026-04-10, the Yes price of the 22°C option dropped from a high of 22c to 6.3c, as forecasts indicated the daily high is unlikely to fall below 23°C, ruling out the cooler range.

Betting on the exact daily high temperature of a specific city is a somewhat niche but established category in prediction markets. While routine for locals, forecasting the exact degree is slightly novel for a general audience.

Between 2026-04-11 11:08 and 2026-04-13 01:03, the price of '28°C or higher' rose from 34.5c to 47.5c, as the approaching resolution date brought updated weather forecasts confirming unusually high temperatures. Between 2026-04-10 08:03 and 2026-04-11 11:08, the price of '28°C or higher' plunged from 51c to 34.5c before rebounding, driven by short-term capital games and minor weather model adjustments. Between 2026-04-09 12:33 and 2026-04-09 13:38, the price of '28°C or higher' surged from 28.5c to 42.5c, likely driven by aggressive speculative buying based on short-term weather model fluctuations or misinterpretation of data, causing extreme options to deviate significantly from fundamentals.

From 2026-04-12 14:13:17 to 2026-04-12 21:48:17, the price of the 16°C or higher option plummeted from 41.5c to 22c, as the latest weather forecasts revised expected highs down to the 14°C-15°C range, significantly reducing the likelihood of extreme high temperatures. From 2026-04-12 14:13:17 to 2026-04-12 21:48:17, the price of the 14°C option surged from 16c to 32.5c, as short-term forecasts indicated a high of 58°F (approx. 14°C), causing its probability to bounce back. From 2026-04-10 04:48:17 to 2026-04-12 14:13:17, the price of the 15°C option surged from 12.5c to 42.5c, as earlier short-term weather forecasts showed a high probability of daytime highs reaching this range. From 2026-04-10 21:03:18 to 2026-04-12 14:13:17, the price of the 14°C option plummeted from 41.5c to 16c, as weather models at the time further revised maximum temperature expectations upward. From 2026-04-10 06:58:17 to 2026-04-12 12:03:16, the price of the 13°C option plummeted from 30.5c to 3.25c, as approaching weather models significantly revised maximum temperature expectations upward, ruling out lower temperatures.

Mainstream meteorological platforms, including the resolution source Wunderground, forecast a high of 58°F (approx. 14.4°C) for London on April 13. Rounding or truncating to the nearest integer would theoretically make 14°C the most expected outcome. However, the prediction market prices 15°C as the favorite (41.5c), with 14°C in second place. This indicates that market participants are expecting a positive deviation from the forecast or local warming effects at the sensor station that exceed the official weather projections, creating a slight divergence.