Highest temperature in Seoul (Incheon) on August 21?

Platform comparison

Market context

Seoul's maximum temperature on 21 August 2026 will be measured at Incheon International Airport Station and resolved against the Daily Observations table on Weather Underground, with settlement occurring at midday UTC on that date. The market currently shows zero probability across all temperature bands, suggesting either sparse trading activity or expectation of extreme heat exceeding available brackets.

August represents Seoul's hottest month climatologically, with mean daily highs near 29°C and historical extremes reaching 39–40°C during heat waves. The city experienced 39.6°C on 8 August 2023 during an exceptional heatwave, whilst more typical August peaks range between 32–36°C. Cross-referencing comparable East Asian prediction markets on temperature outcomes reveals that zero-probability assignments often reflect thin liquidity rather than genuine consensus; when comparable weather markets on other Korean cities or Japanese stations have traded, they've typically shown distributed probability across 5–10°C bands rather than complete concentration at extremes.

Traders should monitor the Asian summer monsoon pattern and any developing high-pressure systems over the Korean peninsula during late August 2026. The Korea Meteorological Administration typically issues extended forecasts three weeks ahead; their mid-August 2026 bulletin will provide the first reliable signal on whether anomalous heat or near-normal conditions are expected. Sea-surface temperatures in the Yellow Sea and any tropical cyclone activity affecting Northeast Asia in early August could materially shift atmospheric conditions, as could shifts in the jet stream position. Historical volatility in August Seoul temperatures—with swings of 8–12°C between consecutive weeks—suggests that current zero-probability pricing may reflect genuine uncertainty rather than settled expectations.

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.

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