Seoul June 1 Low Temp: Will 17°C Hit?

Seoul’s overnight low on June 1 has become one of the sharpest short-term weather markets on Polymarket right now. The 17°C outcome is trading at 57.5% implied probability, and the contract has surged more than 24 percent in 24 hours. Something in the forecast data shifted, and the market is pricing that shift hard.

The market question asks what the lowest temperature in Seoul will be on June 1, 2026, with resolution at 12:00 UTC on that date. The 17°C outcome trades at $0.58 YES and $0.43 NO. Total volume stands at $7,147, with $4,314 of that moving in the last 24 hours. Eleven discrete outcomes span 14°C or below up to 24°C or higher, making this a multi-outcome distribution market where one slice has clearly captured trader conviction.

How the 17°C Contract Works

The contract resolves YES if the official lowest temperature recorded in Seoul on June 1 lands exactly at 17°C. It resolves NO if any other temperature, from 14°C or below all the way to 24°C or higher, is the recorded low. The Korea Meteorological Administration is the primary measurement body for Seoul surface temperature data, and its official daily minimum reading determines resolution.

• YES ($0.58): The Seoul daily low on June 1 is recorded as exactly 17°C.
• NO ($0.43): The Seoul daily low falls on any other outcome, including 16°C, 18°C, or outside that range entirely.

The NO side covers ten competing outcomes. Seoul’s early June overnight lows have historically clustered between 15°C and 20°C, so a reading outside the 17°C bin is statistically more likely in any single trial. The 57.5% YES price reflects a specific, narrow forecast signal, not a broad seasonal average. If ensemble weather models or local forecast services shift that signal by even one degree, capital will exit this bin fast.

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Momentum and Market Signals Pointing at 17°C

The momentum composite here is unusually strong for a hyper-local weather market. The 1-hour gain of 20% and 24-hour gain of 24.5% combine with a trend score of 83.67 to paint a clear picture: a recent numerical weather prediction update, likely from the KMA or the European Centre for Medium-Range Weather Forecasts, locked in a forecast low near 17°C, and traders responded immediately. This is the kind of repricing that happens when a deterministic model run converges on a specific temperature bin the night before resolution.

Total volume of $7,147 is thin by Polymarket standards. Liquidity at $18,043 actually exceeds volume, which means the order book is deeper than current trading activity. Thin volume like this means a single large trade can move the price sharply. The 24-hour volume of $4,314 represents roughly 60% of all capital ever traded in this contract, confirming this is a very recent consensus, not a long-held position.

• The 1-hour and 24-hour momentum both point in the same direction, a +20% and +24.5% composite surge tied to a forecast model convergence near 17°C.
• Liquidity ($18,043) exceeds total volume ($7,147), meaning price is sensitive to any new trade of meaningful size.
• The 83.67 trend score confirms the bullish signal is fresh, not decaying from an older consensus.
• Seoul’s early June climatology places overnight lows most frequently between 16°C and 19°C, so 17°C sits in the modal zone of the distribution.
• With resolution in less than 24 hours, new forecast model runs in the next 12 hours carry the most repricing risk.

Lines Analysis: What the Seoul Forecast Is Telling Us

The data doesn’t care about the politics, and in this case, the data is pretty direct. Short-range numerical weather prediction models for Seoul on June 1 have apparently converged near 17°C for the overnight low, and the market repriced accordingly. Seoul in early June sits in a transitional period between the cool, dry spring pattern and the warmer, more humid pre-monsoon regime. A 17°C overnight low is entirely consistent with that climatological window. The sharp overnight surge in YES pricing suggests the most recent model runs, likely the 00Z or 06Z cycles from a major global model, reinforced rather than contradicted the 17°C call.

What makes the NO side real is resolution granularity. This contract pays on a single integer degree. A forecast of 17.4°C rounds to 17°C, but a forecast of 16.6°C rounds to 17°C too, while an actual reading of 17.5°C or 16.4°C would fall into adjacent bins. Short-range temperature forecasts for a major urban station like Seoul carry a typical error margin of plus or minus 1 to 2 degrees Celsius even 12 hours out. That error range spans three to five bins in this market. Any systematic warm or cool bias in the boundary layer, urban heat island variability, or a passing cloud deck at dawn could shift the official low by one degree and wipe out YES positions entirely.

• The KMA official daily minimum temperature for Seoul is the resolution data point. Any deviation in that reading from 17°C resolves this contract NO.
• The next scheduled KMA forecast update covers tonight’s low. That update carries the highest repricing risk for this contract.
• ECMWF and GFS ensemble spreads for Seoul overnight June 1 will determine whether the 17°C signal holds or widens toward adjacent bins.
• Urban heat island effects in Seoul can lift the official station low by 0.5 to 1.5°C relative to suburban stations. Station-specific bias matters here.
• Any frontal passage or precipitation event affecting Seoul on the evening of May 31 into June 1 would destabilize the forecast and redistribute probability across multiple bins.

Here’s what the measurements are telling us: the market is pricing a specific model outcome, not seasonal climatology. With total volume at $7,147, this is a thin book. The data currently favors YES at 57.5%, but that conviction rests on model runs that will update again before resolution. The market is pricing uncertainty, not science, and in a single-degree resolution contract, uncertainty is the whole game.

LINES VERDICT

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The 17°C outcome has real forecast support and a momentum signal that confirms recent model convergence. A one-degree shift in the actual reading, which is well within normal short-range forecast error, flips this contract entirely.

What the market says: The 57.5% implied probability reflects a specific, model-driven forecast signal that emerged in the last 24 hours. With resolution in under 24 hours and thin volume, this price is volatile and will move on the next KMA forecast update.

Key unknown: The overnight KMA and global model forecast runs covering Seoul’s June 1 low temperature are the single most important data point. If those runs shift toward 16°C or 18°C, capital will exit the 17°C bin immediately.

Scientific Context: Seoul Temperature and Early June Climatology

Seoul’s early June overnight lows have historically ranged between 15°C and 20°C, with the median daily minimum in the first week of June sitting near 17°C to 18°C based on recent decades of KMA station data. The city’s urban heat island effect keeps overnight lows elevated relative to surrounding rural areas. The pre-monsoon transition in late May through mid-June introduces variability as warm, moist air from the south competes with residual cool continental air from the north. That variability is exactly why this market has eleven bins: the distribution is wide enough that no single outcome commands overwhelming probability on climatology alone. The current 57.5% YES price reflects forecast model precision layered on top of that climatological base rate, and it will track model updates closely until the June 1 reading is official.

What moves the price before June 1, 12:00 UTC: Any KMA or major global model forecast update placing the Seoul overnight low outside the 17°C bin will reprice this contract sharply. A convective event, frontal boundary, or unexpected wind shift in the Seoul basin on the evening of May 31 carries the most tail risk for the current YES consensus.

Will the Seoul low hit exactly 17°C on June 1?

The contract pays YES only if the KMA official daily minimum temperature for Seoul on June 1 is recorded as exactly 17°C. At 57.5% implied probability, the market gives it slightly better than even odds based on current forecast model output.

What does the NO contract cover?

NO covers all ten other outcomes, from 14°C or below up to 24°C or higher. A reading of 16°C, 18°C, or any other temperature resolves the 17°C contract NO and pays the corresponding alternative bin instead.

What data event moves this price most?

The next KMA official forecast update and the overnight global model runs covering Seoul’s June 1 minimum temperature carry the most repricing power. These updates typically post between 6 and 12 hours before the resolution window.

When does this market resolve?

Resolution is set for June 1, 2026 at 12:00 UTC, which corresponds to early afternoon Seoul Standard Time, after the official daily minimum temperature for June 1 is recorded and published.

Is volume reliable here?

Total volume of $7,147 is thin. Liquidity at $18,043 exceeds volume, meaning individual trades can move the price sharply. Treat any price move in the next 12 hours as significant, even if it comes from a single position change.