Highest temperature in Seoul (Incheon) on August 21?

Platform comparison

Market context

Seoul's Incheon International Airport will record a daily high temperature on 21 August 2026, measured against historical August patterns for the region. The market currently prices all temperature ranges at 0% YES across the board on Polygon, suggesting either incomplete liquidity or a technical settlement issue rather than genuine trader indifference. Resolution hinges on the Daily Observations table at Weather Underground rather than the Day High & Low summary, a distinction that matters when automated weather stations report granular readings that may differ from rounded figures.

August temperatures at Incheon historically cluster between 26–32°C, with extreme heat events pushing toward 35°C occurring roughly once per decade. The 2018 Korean heat wave saw Seoul reach 39.6°C in early August, whilst more typical recent Augusts have peaked in the 31–33°C range. The settlement window closes at midday UTC on 21 August, creating a narrow window for final readings; traders should note that Incheon's coastal location moderates temperatures compared to inland Seoul, typically running 1–2°C cooler than the capital's city centre.

Relevant catalysts include tropical cyclone activity in the Western Pacific during mid-August, which could suppress temperatures, and the strength of the North Pacific High pressure system. South Korea's Meteorological Administration publishes 10-day forecasts fortnightly; the forecast issued around 11 August will provide the clearest signal for traders positioning ahead of settlement. Recent patterns from 2024 and 2025 August readings at Incheon should anchor baseline expectations, though climate variability means no single historical analogue determines outcomes.

Methodology

This page reviews Highest temperature in Seoul (Incheon) on August 21? across five venues. The live probability is the Polymarket mid-price, sourced directly from the on-chain Polygon order book; the comparison columns benchmark each venue on fee structure, KYC, settlement currency and payment rails. Every CTA routes to Polymarket Scam?, which mirrors the Polymarket order book at 0% fees.

Resolution & payout

Settlement runs on-chain. Polymarket's contract logic separates YES and NO shares as conditional tokens; at resolution the winning share lifts to $1.00 and the losing one to $0. The outcome input comes from the UMA Optimistic Oracle, which secures against bad resolution with a bond + dispute window.

Once finalised, the smart contract pays USDC to the holders' wallets within minutes — no withdrawal fees beyond Polygon network gas. Kalshi settles in USD via CFTC clearance, Betfair in account currency net of commission, Manifold in play-money mana with no cash-out.

UK Frequently Asked Questions

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.

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%.