Highest temperature in Seoul (Incheon) on August 1?

Platform comparison

Market context

The market centres on the day’s **peak temperature at Incheon International Airport**, with settlement determined by the highest reading recorded on 1 August from Wunderground’s Incheon Intl Airport Station feed. Early-day conditions already point to a hot baseline: at about 5 a.m. local time, Incheon was still 27.0°C, while Seoul sat at 27.5°C, indicating little overnight relief and leaving scope for a strong daytime rise.[5][1]

For context, the current **0% YES** looks notably detached from both the prevailing weather pattern and published forecasts. Reuters reported South Korea’s hottest-ever national reading on 31 July, 41.4°C in Yangsan, during an intensifying heatwave, while Korean outlets said Seoul was expected to reach 36°C and Incheon 34°C on 1 August.[6][16] Seasonal averages are much lower—around the high 20s Celsius for Seoul and Incheon in August—so a contract settling on a temperature range above the low-30s would generally need only a normal midday heat spike, not an exceptional extreme.[7][18]

Traders should watch the Korea Meteorological Administration’s short-range updates, because the contract is sensitive to cloud cover, sea breeze effects and the exact timing of any afternoon maximum.[4][8] The main dependency is the airport station itself: coastal Incheon often runs a little cooler than inland Seoul, so small forecast changes can move the settlement band even when the broader regional heat story stays unchanged.[16][10]

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

At resolution the UMA oracle takes over: a proposer posts the outcome with a bond, any token holder can dispute within two hours. Without dispute the result is accepted and the smart contract distributes USDC instantly.

On Kalshi (CFTC-regulated) resolution runs through their in-house clearing engine in USD. Betfair Exchange settles after match end in the account's local currency. Manifold pays no cash — only its in-platform "mana" currency.

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 Best Prediction Markets. 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.

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.