Seoul in mid-May transitions into early summer, with overnight lows historically ranging between 12-15°C. A 17°C low would represent notably warmer conditions than seasonal norms. This market asks a precision question: will Seoul's overnight low be exactly 17°C on May 17, 2026, rather than 16°C or 18°C? Current market odds at 0% YES reveal strong trader consensus that the actual low will miss this precise value. Weather markets resolve against official meteorological data from designated Seoul weather stations, making outcomes directly verifiable and unambiguous. The 0% YES pricing reflects the inherent difficulty of predicting weather within such tight bounds—meteorological forecasts typically have uncertainties of ±1-2°C for daily temperature ranges. A 17°C low would require specific atmospheric conditions: not cold enough for spring rain systems, not warm enough to suppress cooling, but precisely balanced. The market structure rewards traders who correctly anticipate whether actual conditions will be warmer, cooler, or exactly 17°C.
What factors could move this market?
Seoul's weather in May is transitional. Spring monsoons can still influence early May, but by mid-May, the peninsula typically settles into warmer, drier conditions as the subtropical Pacific anticyclone strengthens. Overnight lows average 12-14°C in mid-May, so a 17°C low represents a warm outlier—approximately 3-5°C above typical. For the low to reach 17°C, Seoul would need sustained warmth through the night: either a warm ocean current influence bringing maritime tropical air, a high-pressure system trapping heat, or unusually weak nocturnal cooling due to cloud cover and humidity. Conversely, cooler lows of 10-12°C remain likely if frontal systems bring cooler air masses or if clear skies allow efficient ground radiation and cooling. Recent May patterns in Seoul show lows clustering tightly between 11-16°C; reaching exactly 17°C is statistically less probable than nearby values. The 0% market odds suggest traders view a 17°C low as an extreme tail outcome—less likely than adjacent temperatures like 16.5°C or 17.5°C, though rounding could push observed readings near that threshold. However, the market's binary structure creates asymmetry: minor forecasting errors that land at 16°C or 18°C both resolve NO. Weather station thermometers record to 0.1°C precision, but the market likely uses official reported daily lows rounded to the nearest degree, adding ambiguity at boundaries. If Seoul's true low is 16.8°C, it may or may not round to 17°C depending on rounding conventions. This boundary uncertainty compounds the already-difficult task of hitting a precise temperature target. The 24-hour volume of $517 and modest liquidity of $8,583 indicate limited market participation—consistent with a niche daily weather prediction. Serious weather forecasters would assess May 17 conditions using atmospheric models and seasonal pattern recognition; the current 0% YES odds likely reflect model consensus that the most probable low falls in the 11-15°C band, making 17°C a low-probability event that sophisticated traders are avoiding entirely.
What are traders watching for?
Korea Meteorological Administration's official minimum temperature report for Seoul on May 17, released May 18 morning.
Incoming weather systems May 16–17: watch for cold fronts, pressure drops, or warm maritime air masses.
Recent Seoul low-temperature trend through May 16; if pattern shows warming, higher odds for 17°C outcome.
Cloud cover and nocturnal cooling May 16 night; clear skies suppress warming; overcast enables heat retention.
How does this market resolve?
Market resolves YES if Korea Meteorological Administration reports Seoul's official low temperature on May 17 as exactly 17°C. Any other reading resolves NO.
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