Highest temperature in Seoul (Incheon) on August 8?

Platform comparison

Market context

Seoul’s late-summer heat is the real-world event here: the contract settles on the **highest temperature** recorded at Incheon Intl Airport Station on 8 August, with the Weather Underground Daily Observations table controlling if it differs from the Day High & Low summary. August is normally Seoul’s hottest month, with typical highs around 30°C and a recorded August high of 39.6°C in the city’s climate record, so the contract’s 0% YES imply a move into a very warm but not extreme band at the time of pricing.[2][15]

For context, recent and historical August data still point to a wide upside range rather than a tightly anchored daily maximum. Weather Underground’s Seoul history page is the relevant settlement source, while other weather sites show comparable early-August forecasts around the mid-30s °C and long-run averages near 30°C, with the possibility of a hotter-than-normal afternoon if cloud cover breaks late.[14][2] That matters because the market resolves on a station reading, not a city average, and airport observations can diverge from downtown Seoul by a degree or more.

Traders should watch the local forecast evolution, rainfall timing, and any warm-sector intrusion or thunderstorm outflow that could cap the daytime high. In July and August, Korea often sits in a humid monsoon pattern with heavy rain episodes mixed with intense heat, so a forecast shift in cloud cover or precipitation can move the final max temperature materially.[17][18] On-chain, settlement will be in USDC, so the practical risk is not price discovery in BTC or ETH itself but the market’s ability to price a binary weather outcome cleanly before the noon UTC window closes.

Sources: 1 · 2 · 3 · 4 · 5

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%.