Highest temperature in Seoul (Incheon) on August 18?

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Market context

On 18 August 2026, the highest temperature recorded at Incheon International Airport Station will determine which range this market resolves into. The settlement mechanism uses Weather Underground's Daily Observations table as the authoritative source, bypassing the Day High & Low summary section to eliminate ambiguity. Resolution occurs at 12:00 UTC on that date, with USDC settlement following confirmation of the official reading.

Seoul's August climate is consistently hot and humid, with historical highs typically between 28–34°C. The 0% crowd probability suggests traders are either awaiting range options or treating this as a placeholder market. Comparable August temperature markets in East Asia have shown that extreme heat events (35°C+) occur in roughly 15–20% of years during this period, whilst readings below 26°C are rare. The current probability distribution likely reflects uncertainty about which specific range brackets are available rather than genuine doubt about whether a temperature will be recorded.

Traders should monitor Korean Meteorological Administration forecasts released in early August 2026, which typically provide 10-day outlooks with reasonable accuracy for daily maxima. Tropical cyclone activity in the Western Pacific during mid-August can suppress temperatures or drive sudden spikes; the typhoon season's timing will be material. Real-time funding rates on weather derivative contracts, if available on major crypto derivatives platforms, may signal institutional positioning ahead of settlement. Any unusual atmospheric patterns flagged by regional weather services in the week prior should prompt position review.

Methodology

This page reads Highest temperature in Seoul (Incheon) on August 18? on-chain. Polymarket's quote comes directly from the Polygon order book — the only comparable venue with on-chain settlement. Kalshi (USD, off-chain), Betfair (GBP/EUR, off-chain) and Manifold (play-money) are listed alongside for venue context. Every CTA routes to BTC Prediction, which mirrors the Polymarket order book directly.

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.

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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.

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