Highest temperature in Seoul on July 18?

Platform comparison

Market context

Seoul's peak temperature on 18 July 2026 will be measured at Incheon International Airport Station and resolved against historical weather data from Wunderground. The settlement window closes at midday UTC, meaning traders must account for the full calendar day's readings across all hours before the cutoff. This measurement point sits approximately 50 kilometres west of central Seoul and typically records temperatures 1–2°C lower than the city centre due to coastal proximity and maritime influence.

Historical July temperatures at Incheon average 28–29°C for daily highs, with extreme readings occasionally reaching 34–36°C during heat waves. The 0% crowd probability suggests either market dysfunction or genuine uncertainty about whether any temperature range will be selected—a technical possibility if the market fails to receive valid settlement data. Traders should verify Wunderground's historical data accessibility for this specific station and confirm the exact temperature brackets offered, as API-dependent resolution requires precise threshold matching.

Programmatic traders should monitor South Korean meteorological forecasts from the Korea Meteorological Administration (KMA) in early July 2026, which typically issue extended outlooks by mid-month. Pacific typhoon tracking becomes relevant if tropical systems approach the Korean peninsula, potentially suppressing temperatures significantly below seasonal norms. Setting conditional orders based on KMA heat-wave alerts or upper-air pattern shifts would allow automated position adjustment as the settlement date approaches, though the long lead time means current probability signals carry minimal predictive weight.

Methodology

We track Highest temperature in Seoul on July 18? across the five venues with material prediction-market liquidity. The probability shown is the live Polymarket mid; the comparison rows summarise how each venue treats the underlying contract — fees, KYC thresholds, settlement currency, deposit options. The highlighted row marks the cheapest route into Polymarket's order book.

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?

Polymarket is geo-blocked in the US/UK/EU. The easiest 0%-fee broker into the same order book is Polymarket Review UK. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

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.

What does Polymarket cost to trade?

Polymarket itself charges 0% — the only cost is the Polygon network fee, typically under $0.01 per transaction. Off-chain venues like Kalshi or Betfair charge 2-7% commission.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like Polymarket Review UK trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.