Highest temperature in Seoul (Incheon) on August 9?

Platform comparison

Market context

Seoul’s high on 9 August is being priced against a live heatwave backdrop rather than a normal summer profile, with recent Korean reporting saying temperatures across the country were still expected to reach up to 36°C on 8–9 August after an early-August surge. Reuters said Seoul was forecast to hit 39°C on 6 August, close to the city’s record high of 39.6°C, while KMA-linked coverage showed Seoul already posting 36.3°C on 3 August and 39.9°C in Yongsan on 6 August, which helps explain why the market is clustered around the low-to-mid 30s rather than the month’s usual average. [7][19][18][12]

The current 0% YES price is only sensible if traders are reading the contract mechanically as a single-day Celsius bucket on the Weather Underground daily observations table at Incheon Intl Airport Station, with settlement on the highest recorded temperature before the cutoff. KMA short-range forecasts and the Reuters heatwave coverage are the main catalysts to watch because they can shift intraday expectations for whether the station prints 33°C, 34°C or higher; in prediction markets, the final USDC payout is determined by the exact observed bucket, so late-morning updates and any revision in the observational record matter more than headline summaries. [5][7][3]

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%.