Highest temperature in Seoul (Incheon) on August 12?

Platform comparison

Market context

Seoul's summer heat peaks in August, with daily highs typically ranging between 28–32°C at Incheon International Airport, the official measurement station. On 12 August 2026, the highest temperature recorded in the Daily Observations table will determine settlement; Weather Underground's granular hourly data takes precedence over summary figures, a distinction material to resolution accuracy given occasional discrepancies between real-time and aggregated readings.

Historical August temperatures at Incheon show clustering around 29–31°C on ordinary days, with extreme heat events pushing above 33°C occurring roughly once per decade. The 0% crowd probability suggests traders are pricing in either a specific upper-range threshold or treating the market as illiquid relative to more liquid weather derivatives. Comparable markets on crypto weather platforms show similar compressed probabilities for narrow temperature bands in monsoon-affected regions, where atmospheric variance compounds forecasting difficulty.

Catalysts include the East Asian summer monsoon pattern, which typically peaks in early August and can suppress temperatures through cloud cover and precipitation, and any tropical cyclone activity affecting the Korean peninsula in early-to-mid August. The Korea Meteorological Administration publishes extended forecasts weekly; their 10-day outlook issued around 2–3 August will provide the most actionable signal for traders. USDC settlement mechanics mean basis risk between spot weather outcomes and on-chain execution remains minimal, though settlement lag depends on Weather Underground's data publication schedule, typically finalised within 24 hours of the observation date.

Methodology

Methodologically this overview focuses on on-chain pricing: Polymarket's live mid comes from the Polygon conditional-token order book and settles automatically in USDC. The other three venues — Kalshi, Betfair, Manifold — sit alongside as off-chain reference points so you can see how the contract translates across regulatory and settlement regimes.

Resolution & payout

Settlement is on-chain via UMA Optimistic Oracle. A proposer posts the outcome with a bond, a two-hour dispute window opens, then the smart contract lifts winning conditional tokens to 1 USDC and sends payments to holders' wallets automatically. No withdrawal fees beyond Polygon gas.

Off-chain venues (Kalshi, Betfair, Smarkets) settle in local fiat through bank-side clearing — faster than SWIFT, slower than on-chain. Manifold pays no real cash.

UK Frequently Asked Questions

What are crypto prediction markets?

Crypto prediction markets are on-chain smart contracts where you buy YES or NO shares on a future crypto event (e.g. "BTC above $100k by year-end"). The market price between 0¢ and 100¢ is the implied probability.

Why USDC and not ETH or USDT?

USDC is the Polygon standard — audited reserves (Circle, monthly attestation), deepest order book, low gas costs. ETH volatility would distort probability quotes; USDT has thinner Polygon liquidity than USDC.

Is Polymarket legal in the UK?

Polymarket is accessible to UK traders but is not UKGC-licensed. It operates under US CFTC jurisdiction. UK residents face no domestic legal prohibition on using it, but UKGC consumer protections do not apply. For UKGC-regulated alternatives, Betfair Exchange and Smarkets offer similar prediction-style markets.

Do I pay tax on prediction market profits in the UK?

UKGC-licensed platform profits (Betfair, Smarkets) are typically tax-free gambling winnings for UK individuals. Polymarket profits involve USDC crypto transactions, which HMRC treats as Capital Gains Tax events. Keep full transaction records and report via Self Assessment if gains exceed £3,000 per tax year.

How do I deposit on Polymarket from the UK?

UK traders typically fund Polymarket via Coinbase UK, Kraken or Revolut — buying USDC with GBP and transferring to a Polygon-compatible wallet (MetaMask, Coinbase Wallet). Polymarket's onboarding walks you through the bridging process. Typical GBP-to-USDC conversion costs 0.5–1%.