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, the official weather reference point for the metropolitan area. Mid-July represents the height of South Korea's monsoon season, with typical daily highs ranging from 28–32°C, though heat waves can push readings several degrees higher. The 0% crowd probability suggests traders are either uncertain about the specific temperature bands available or treating this as a straightforward seasonal forecast with limited surprise potential.

Historical July records at Incheon show the airport station has recorded temperatures exceeding 35°C on roughly one in three days during mid-month periods over the past two decades, with extreme heat waves occasionally reaching 37–39°C. The 2018 heat wave saw consecutive days above 35°C across the region, whilst cooler monsoon patterns have produced peaks near 26–28°C. These variations mean the outcome depends heavily on whether a high-pressure system or active low-pressure trough dominates the week leading up to 18 July.

The Korea Meteorological Administration issues extended forecasts approximately 10 days in advance, with meaningful updates arriving around 12–14 July. Traders should monitor whether tropical systems develop in the Western Pacific, as these can suppress temperatures through cloud cover and rainfall, or whether the Tibetan high-pressure system extends eastward, which typically drives sustained heat. Real-time atmospheric data from the GFS and ECMWF models will sharpen probability estimates in the final week.

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

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.

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.

Do I need to KYC for this market?

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