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 assigned to one of several temperature bands. The market currently shows zero probability assigned to any outcome, reflecting either minimal trading activity or genuine uncertainty about which range will ultimately contain the day's peak reading. Resolution depends on historical weather data from Wunderground, with the settlement window closing at midday UTC on the resolution date itself.

Seoul's late May climate typically produces highs between 24°C and 28°C, though the city has recorded temperatures as high as 30°C during heat waves in this period. Historical May 31st data from Incheon shows considerable year-to-year variation; the airport station recorded 29.4°C on 31 May 2018 but only 22.1°C on 31 May 2019. This volatility explains why prediction markets struggle to converge on a single probability band without active participation from weather-informed traders. Comparable spring-to-early-summer transitions in East Asia suggest that upper-range outcomes (28°C+) occur in roughly one-third of years, whilst cooler outcomes cluster around seasonal norms.

Traders monitoring this contract should track seasonal weather pattern forecasts released by the Korea Meteorological Administration in the weeks preceding May 2026, particularly any signals about high-pressure systems or monsoon onset timing. The settlement window's noon UTC closure means traders must account for the time-zone offset between London and Seoul when interpreting final readings. No major meteorological events or climate anomalies are currently flagged as dependencies for this specific date.

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

Polymarket-based markets settle through the UMA Optimistic Oracle on Polygon. A proposer submits the outcome, a two-hour challenge window opens, and unchallenged proposals finalise the resolution. Payouts settle automatically in USDC the moment the result is final — no bookmaker, no delay.

Kalshi-based markets settle in USD via the CFTC-regulated clearinghouse. Betfair Exchange settles in GBP/EUR net of commission. Manifold is play-money and does not pay out real funds.

FAQ

Where can I trade this market with the lowest fees?

On Best Prediction Markets, 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 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.

What does it cost to trade on Best Prediction Markets?

Zero. Best Prediction Markets routes every order to the live Polymarket order book; the only cost is the Polygon network fee, typically under $0.01 per transaction.

How fast are USDC deposits?

Polygon credits deposits after 12 confirmations — usually under 30 seconds. Withdrawals follow the same path and land back in your wallet within minutes.

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.