While checking the weather is a common daily activity, placing bets on the exact high temperature of a specific city on a given day is a relatively niche prediction market activity that most people do not actively ponder.

April 13, 2026 - April 14, 2026: The price for 19°C surged from 24c to a peak of 41c before falling to 36.5c, while 18°C rose from 14c to 27c. This volatility was driven by initial weather models predicting warmer highs (around 19°C), followed by subsequent cooler forecast updates that redirected capital towards the 17°C and 18°C options.

The market still prices 19°C as the frontrunner (36.5c), yet the latest official Wunderground forecasts explicitly show the expected high for April 15 has been revised down to 63°F-64°F (17°C-18°C) [2]. There is a lag in the market's reaction to the updated meteorological models, causing a significant divergence between the priced expectations and the current weather reality.

April 13, 2026 - April 14, 2026, the price of the 28°C option plunged from 34c to 18c (before slightly recovering to 23c), as weather models narrowed their forecast ranges for the peak temperature as the date approached, reducing the probability of higher extremes and shifting the center towards 26°C-27°C. April 13, 2026 - April 14, 2026, the price of the 30°C option dropped from 12.5c to around 2.5c, also due to increased certainty in weather forecasts ruling out the likelihood of unusually high temperatures.

While the title specifies 'Seoul', the resolution rules explicitly mandate data from the Incheon International Airport Station (RKSI). Incheon is an island/coastal area and may have different temperatures compared to central Seoul, potentially misleading casual bettors. Additionally, integer rounding rules could cause edge-case disputes.

April 13, 2026 - April 15, 2026, the price of the '20°C' option surged from 15c to 40.5c, and the '21°C or higher' option also spiked from 23.15c to 42.5c. This was driven by near-term weather forecast revisions that upgraded the expected high temperatures to 20°C or more. April 13, 2026 - April 15, 2026, the price of the '18°C' option plummeted from 30.5c to 1.2c, as the market almost entirely priced out this lower temperature range following the warmer forecasts.

April 13, 2026 - April 14, 2026, the price of the 23°C option surged from 27.5c to 40.5c, as approaching the resolution date, updated meteorological models further solidified 23°C as the most likely high-temperature bracket. April 13, 2026, the price of the 24°C option plummeted from 31c to 11.5c before rebounding to 24.5c. This was caused by conflicting updates from different weather forecasting sources on that day, leading to short-term severe volatility in market expectations.

Between April 13 and April 14, 2026, the price of 16°C dropped from 33.5c to 11.5c before rebounding to 21.5c, 15°C plummeted from 22c to around 3.9c, 17°C rose from 32c to 48.5c before settling at 37.5c, and 18°C surged from 9.5c to 35.5c before settling at 29.5c. The reason is that as the expiration date approaches, updated weather forecasts have further confirmed an upward revision in expected high temperatures (around 62°F/17°C), eliminating cooler possibilities and significantly increasing the likelihood of 17°C and 18°C. Between April 13 and April 14, 2026, the price of 13°C fell from 12.5c to near zero (0.2c). The reason is that updated forecasts have confidently shifted the expected high temperature to the 16°C-18°C range, virtually eliminating the chances of cooler outcomes.