Highest temperature in Seoul on May 31?

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Market context

On 31 May 2026, Seoul's highest temperature will be measured at Incheon International Airport Station and resolved against pre-defined Celsius ranges. The crowd currently assigns zero probability to any outcome, suggesting either extreme uncertainty about which temperature band will occur or insufficient trader participation. May in Seoul typically sees daily highs between 24–28°C as the region transitions toward summer, though variability remains substantial depending on atmospheric patterns and whether warm air masses from the south dominate.

Historical May temperatures at Incheon show the month can produce highs ranging from 20°C during cooler years to 31°C during warm spells, with the 30-year average around 25–26°C. The absence of any meaningful probability assignment across temperature bands is unusual for a weather market with a defined settlement date and transparent data source; comparable prediction markets on European weather stations typically see distributed probabilities reflecting seasonal norms and recent climate trends. This flatness suggests the market may lack sufficient liquidity or trader familiarity with Korean meteorological patterns.

Traders should monitor late-May weather forecasts from the Korea Meteorological Administration and track any El Niño or La Niña signals that could shift regional temperatures. Atmospheric pressure systems moving across East Asia in the weeks preceding 31 May will be the primary driver of whether Seoul experiences a cool, average, or warm day. Current global climate indices and any significant heat-wave warnings issued by Korean authorities in May 2026 would serve as concrete catalysts for reassessing the probability distribution across temperature bands.

Methodology

We track Highest temperature in Seoul on May 31? on the five venues with material liquidity for prediction markets. Live odds come from the Polymarket Polygon order book — the only source that ships real-time data under an open licence. For Kalshi, Betfair and Manifold we list platform attributes (fee, KYC, settlement, payment) instead of fabricated odds, because their APIs use non-comparable contract definitions.

Resolution & payout

Settlement runs on-chain. Polymarket's contract logic separates YES and NO shares as conditional tokens; at resolution the winning share lifts to $1.00 and the losing one to $0. The outcome input comes from the UMA Optimistic Oracle, which secures against bad resolution with a bond + dispute window.

Once finalised, the smart contract pays USDC to the holders' wallets within minutes — no withdrawal fees beyond Polygon network gas. Kalshi settles in USD via CFTC clearance, Betfair in account currency net of commission, Manifold in play-money mana with no cash-out.

FAQ

Where can I trade this market with the lowest fees?

On Best Prediction Markets UK, which mirrors the Polymarket order book at 0% fees. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

Is this market available outside the US?

Best Prediction Markets UK is available in most jurisdictions where Polymarket isn't directly accessible. Polymarket itself is geo-blocked in the US/UK/EU. Always check local regulations.

How does resolution work?

Through the UMA Optimistic Oracle on Polygon: a proposer submits the outcome, a two-hour challenge window opens, and USDC payouts settle automatically once the result is final.

What's the difference between YES and NO shares?

A YES share pays $1.00 if the event happens, $0 otherwise. A NO share pays $1.00 if the event doesn't happen. The market price between 0¢ and 100¢ is the implied probability.

How reliable are the quoted odds?

The YES/NO percentages are the live mid-prices of the Polymarket order book. On deep markets they move every few seconds; on thinner ones you'll see short plateaus.