Seoul Low Temperature on May 10: Will 11C Hold?

Seoul’s overnight temperature on May 10 has become the most precisely traded weather event on Polymarket right now. The 11°C outcome carries a 63.5% implied probability, meaning traders have put meaningful capital behind a single-degree temperature band in a city known for sharp spring variability. That kind of precision is unusual. It also makes this market one of the most volatile weather contracts active today.

The contract resolves at 2026-05-10 12:00:00, giving almost no time for additional data to arrive before settlement. With total volume at $15,239 and 24-hour volume at $9,220, most of the trading activity has happened in the last day. The market is pricing uncertainty, not science, and right now the uncertainty is concentrated inside a two-degree window.

How the Seoul May 10 Temperature Contract Works

The contract asks one question: what is the lowest temperature recorded in Seoul on May 10, 2026? Traders select from eleven discrete temperature bands, from 9°C or below up to 19°C or higher. The 11°C band is the current leader at 0.64 (YES) versus 0.37 (NO). Resolution is determined by official temperature measurement for Seoul on that date.

• YES (11°C lowest temperature): Priced at 0.64, implying a 63.5% probability. Pays out if the official Seoul low on May 10 falls within the 11°C band.
• NO (any other outcome): Priced at 0.37, implying a 36.5% probability. Pays out if the Seoul low lands on any other band, including 10°C, 12°C, or any adjacent value.

The NO side is essentially a bet that Seoul’s temperature misses the 11°C band entirely. Seoul’s spring overnight lows in early May typically range between 10°C and 14°C, which means the winning band could plausibly shift one or two degrees in either direction. The Korea Meteorological Administration tracks official temperature records, and any forecast update from that agency before resolution could reprice this contract sharply.

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Momentum and Market Signals

The momentum composite here is striking. A combined signal of plus 25.5% in one hour, plus 27.0% in 24 hours, and a trend score of 83.67 points to a single sharp repricing event, not gradual drift. That kind of acceleration on a short-duration weather contract usually means a credible forecast update hit traders at roughly the same time. The 11°C band absorbed most of that capital.

Total volume sits at $15,239, with $9,220 of that arriving in the last 24 hours. That is thin volume by most standards, and thin volume means the price can move sharply on a single large bet or a new forecast reading. The $1,679,717 in liquidity looks deep relative to volume, which suggests the order book is not being depleted, but the price discovery here is being driven by a small number of participants.

• 1-hour change: Plus 25.5% on the 11°C outcome. This is a fast repricing, not a slow grind upward.
• 24-hour change: Plus 27.0%, confirming the move was concentrated and recent, not spread across the trading day.
• Trend score of 83.67: Places this contract in the upper tier of momentum among active Polymarket weather markets.
• Volume concentration: $9,220 of the $15,239 total arrived in the last 24 hours, flagging a late-breaking catalyst, most likely a regional forecast update.
• Liquidity depth: $1,679,717 in the order book means the spread is unlikely to blow out on moderate trades, but price remains sensitive to new information.

Lines Analysis: Seoul Temperature on May 10

Korea Meteorological Administration forecasts for early May 2026 have Seoul sitting in a mild spring pattern, with overnight lows trending in the 10°C to 13°C range. The 11°C band sits near the center of that forecast distribution, which explains why traders have converged on it. Historical Seoul May lows cluster in this zone regularly during the first two weeks of May, with cold front passages occasionally pushing readings toward 9°C or below and warm air advection sometimes lifting lows to 14°C or 15°C.

What makes the NO side real is the band structure itself. The contract pays out on a single-degree bucket. If the official Seoul low registers 10.5°C, it resolves to 10°C. If it registers 11.4°C, it resolves to 11°C. The rounding conventions for official Korean temperature records matter here. A forecast centered on 11°C still carries meaningful probability of resolving to an adjacent band.

• Korea Meteorological Administration forecast update: Any shift in the agency’s official overnight low projection for May 10 will immediately reprice this contract.
• Cold front timing: A front arriving earlier than forecast could push the low toward 9°C or 10°C, collapsing the 11°C position.
• Warm air hold: If southerly flow persists longer than modeled, the low could settle at 12°C or 13°C.
• Resolution methodology: Confirm which Seoul station and which measurement convention determines the official low. Station selection can shift outcomes by one degree.
• Final 24-hour model runs: GFS and ECMWF output for Seoul on May 9 evening will be the last credible signal before resolution.

The $15,239 in total volume is not deep enough to treat this market as a reliable crowd forecast. Here’s what the measurements are telling us: traders repriced sharply toward 11°C within the last 24 hours, most likely on a model update that put the overnight low squarely in that band. But a one-degree weather contract in a city with real spring variability carries real resolution risk regardless of forecast confidence.

LINES VERDICT

Favored Outcome: Seoul Low at Eleven Degrees Celsius

The momentum signal is clear and the forecast distribution supports the 11°C band, but this market resolves on a single observed measurement inside a one-degree window. That structure keeps the NO side meaningful regardless of probability.

What the market says: A 63.5% implied probability reflects genuine trader conviction toward 11°C, driven by a sharp repricing in the last 24 hours. Given the resolution at 2026-05-10 12:00:00 and thin total volume, a single forecast revision in the next few hours could shift this probability by ten points or more.

Key unknown: The Korea Meteorological Administration’s final overnight low forecast for Seoul on May 10 is the single data point that will determine whether the 11°C band holds or traders rotate to an adjacent outcome.

Scientific Context

Seoul sits in a continental monsoon climate zone where early May temperatures transition rapidly. The city’s overnight lows in the first two weeks of May average around 10°C to 12°C based on historical Korea Meteorological Administration records. Cold air outbreaks from the north remain possible through mid-May, and southerly flow events can push lows several degrees above the seasonal mean. The data doesn’t care about the politics of climate attribution here. What matters for this contract is a 12-hour forecast window and one official temperature reading.

Frequently Asked Questions

• What does a 63.5% probability mean for this contract? It means traders currently assign roughly a two-in-three chance that Seoul’s official low on May 10 lands in the 11°C band. That is a majority view, not a certainty.
• What happens if the NO contract pays out? Any outcome other than 11°C resolves the NO position as a winner. That includes 10°C, 12°C, or any other band across the full eleven-option range.
• What data or event would move this price most? A Korea Meteorological Administration forecast update placing the overnight low firmly at 10°C or 12°C would rapidly shift capital away from the 11°C position.
• When does this contract resolve? Resolution is set for 2026-05-10 12:00:00. The contract settles based on the official Seoul temperature record for that date.
• Is $15,239 in volume enough to trust this price? Total volume is thin. Thin markets can move sharply on a single trade or new forecast data. Treat the 63.5% probability as a directional signal, not a precise scientific estimate.

This analysis reflects market conditions as of 2026-05-09 11:13:59. Prediction market probabilities are volatile and shift as new data and regulatory decisions emerge, especially as the 2026-05-10 12:00:00 resolution date approaches. Lines.com does not accept bets or provide financial or gambling advice. All market outcomes are uncertain.