Highest temperature in Seoul (Incheon) on August 4?

Platform comparison

Market context

Polymarket is pricing this Incheon Airport temperature contract at **0% YES**, which means the market is currently assigning no weight to a settlement in the target range. On the platform, the trade is settled in **USDC** on **Polygon** through conditional tokens, so the relevant question is not whether Seoul feels hot in general, but whether the official Wunderground observation at **Incheon Intl Airport Station** lands inside the specified band by the resolution deadline.

The historical and forecast backdrop is broadly supportive of a warm outcome, even if the exact band still matters. Wunderground’s settlement source is the airport station reading, and comparable August conditions in Seoul and Incheon are usually warm to hot, with August averages in Seoul around the mid-20s Celsius to low 30s depending on the source and period.[1][14][19] For 4 August 2026, Korean media forecasts point to highs of **37°C in Incheon** and **38°C in Seoul**, with heatwave conditions persisting across the capital area.[3] That implies the market hinges on whether the airport reaches a sufficiently high afternoon maximum, not just on citywide heat.

For traders, the main catalysts are the day’s official forecast updates, any heat advisory or rain-shower changes, and the timing of cloud cover or sea-breeze effects around Incheon, which can cap highs relative to inland Seoul. SBS reported a serious heat wave warning from 11:00 local time and afternoon showers in parts of the region, while Asiae said rain would not materially relieve the heat.[2][3] The key mechanics are straightforward: if the airport’s observed maximum rises through the afternoon before the settlement window closes, the conditional tokens pay according to the band that contains that final recorded high.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

Methodologically we separate two layers: the live probability (Polymarket mid-price) and the platform attributes (fee, KYC, settlement currency, payment rails). That keeps the comparison honest — a single canonical probability across the row, with the venue-by-venue trade-offs spelt out in the columns next to it.

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

Is this market available outside the US?

Polymarket itself is geo-blocked in the US/UK/EU. Always check the legal status of prediction markets in your jurisdiction before trading.

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 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.

Do I need to KYC for this market?

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