Highest temperature in Seoul (Incheon) on August 1?

Platform comparison

Market context

Polymarket is pricing the highest temperature at Incheon Intl Airport Station on 1 August at **0% YES**, even though the contract settles against a single afternoon reading and pays out in **USDC** via **Polygon** conditional tokens. That leaves the market effectively saying there is no visible chance of the airport station printing a temperature that lands in the YES range before the settlement window closes at 12:00 UTC.

The historical frame argues for caution on either side of an extreme view. Seoul and nearby stations have produced severe August heat before: Seoul reached **39.6°C** on 1 August 2018, and South Korea logged **40.3°C** the same day at Hongcheon, showing that early-August spikes are possible in the region[1][9]. At the same time, broader August norms are much lower, with Seoul’s typical highs around the upper 20s to low 30s Celsius and Incheon forecast ranges commonly centred near the high 20s[2][11][12]. For a station-specific contract like this, the exact airport observation matters more than the city narrative, because coastal influence can keep Incheon a few degrees below inland Seoul on the same day.

Traders should watch the Korea Meteorological Administration, airport conditions, and whether heat advisories persist through the morning and early afternoon, since the market resolves on the day’s maximum rather than the morning reading. Local reporting on 1 August already described a nationwide heatwave, with Seoul and Incheon both starting the day warm and tropical-night conditions across the region[3]. That sort of setup can support a higher daily maximum, but cloud cover, sea breeze and rainfall risk around Incheon can still cap the airport reading below inland highs, so the outcome is driven by the day’s intraday weather rather than the headline forecast alone.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in Seoul (Incheon) on August 1? 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

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?

Polymarket is geo-blocked in the US/UK/EU. The easiest 0%-fee broker into the same order book is Kalshi 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.

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 Kalshi UK trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.