The title asks for the temperature in Seoul, but the resolution rules strictly specify data from Incheon International Airport on Wunderground. Given the geographical distance (Incheon is coastal), there are often slight temperature variations between the two. Bettors who only read the title might fall into this location-mismatch trap.

April 21, 2026 - April 22, 2026, the price of 18°C dropped from 14c to 4.4c, 19°C dropped from 16c to 6.5c, and 22°C rose from 18c to 27c. The reason is that as the date approaches, weather forecast data becomes more definitive, and the market expects the highest temperature to be higher than previously predicted, leading to a sell-off in lower temperature options and increased buying in higher temperature options. Over the past 3 days, there have been no extreme price swings exceeding 10c for any option, as prices have smoothly adjusted in response to standard meteorological forecast updates.

There is a mild divergence between the market expectation (favoring 22°C and 23°C) and some mainstream public weather forecasts (such as Google's default 21°C/70°F forecast). This could be due to micro-climate historical adjustments specific to the Wunderground SAEZ station, or market participants relying heavily on a warmer weather model (such as AccuWeather's higher estimates).