Will Seoul's maximum temperature reach exactly 20°C on May 18, 2026? The prediction market currently prices this outcome at just 1%, suggesting traders believe it's highly unlikely the city's daily high will be that precise temperature. Seoul in mid-May typically sees highs ranging from 22-28°C as late spring transitions toward early summer. A 20°C maximum would represent a cooler-than-normal day, possibly driven by a passing cold front or sustained cloud cover pushing back the seasonal warmth. The 1% odds reflect both the specificity of the threshold and historical climate patterns — while a 20°C day isn't impossible in late May, it falls well below typical seasonal norms for this period. Recent years have shown May temperatures in Seoul climbing earlier in the month as regional warming patterns intensify. The current market spread suggests traders are essentially betting against an unusually cool day within a very narrow temperature band. This market resolves based on official Seoul weather station data, requiring precision to the degree Celsius. The low odds and tight liquidity indicate modest trading interest in this niche weather forecast.
What factors could move this market?
Seoul's climate in May occupies a transitional zone between spring and summer, with historical temperature data showing significant variation depending on synoptic weather patterns. The meteorological spring in Korea officially ends in May, transitioning toward the warmer monsoon season. The 20°C threshold is notably specific — it falls at the lower boundary of Seoul's typical May highs but remains climatically plausible during anomalous cold events. The Korean Meteorological Administration tracks daily maximum and minimum temperatures at Seoul's central observatory, the official data source for market resolution. May 18 specifically represents mid-to-late spring, well past the period of severe temperature swings. Factors supporting a YES outcome (20°C or below) would include a strong Siberian high-pressure system extending south, an active cold front passage, sustained cloud cover and rainfall, or a delayed spring warm-up due to persistent upper-level troughs. These conditions do occur in late May but are relatively uncommon given the season's general warming trend. A low-pressure system centered over northern China combined with a cut-off cold upper-level pattern could suppress temperatures significantly. Historical records from recent years (2020-2025) show only occasional days below 20°C in May, typically clustered in early-to-mid May rather than the May 18 timeframe. Factors pushing toward NO (higher than 20°C) include the strong seasonal warming trend, high-pressure ridging over East Asia, clear skies encouraging diurnal heating, and warmer-than-average conditions that have become increasingly frequent in recent decades. Most May 18ths in Seoul's recent climate record show highs between 22-26°C. Traders holding NO odds are essentially betting on normal or above-normal conditions, which aligns with both seasonal climatology and the broader warming patterns observed across East Asia. The 1% odds suggest near-consensus that 20°C represents an outlier outcome. The market's relatively low volume and modest liquidity indicate this is a specialized forecast attracting weather forecasters, climate data enthusiasts, and prediction market specialists. Early May forecasts become increasingly reliable 5-7 days before the event, suggesting the market's pricing could shift meaningfully if weather models show unexpected cold patterns developing.
What are traders watching for?
Monitor Seoul weather forecasts May 15-18 for unexpected cold fronts or low-pressure systems that could suppress highs below 22°C.
Watch for Siberian high-pressure systems or Asian jet stream patterns that might bring cooler air to the Korean peninsula.
Official Korean Meteorological Administration maximum temperature reading for Seoul on May 18 resolves the market precisely at the 20°C threshold.
Historical May 18 highs in Seoul range 22-26°C; a 20°C outcome would require anomalous spring weather conditions.
How does this market resolve?
The market resolves on May 18, 2026 based on the official daily maximum temperature recorded by the Korean Meteorological Administration's Seoul observatory. YES wins if the high is exactly 20°C; any other value resolves NO.
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