Highest temperature in Seoul (Incheon) on August 18?

Platform comparison

Market context

Seoul's weather on 18 August 2026 will be shaped by the typical intensity of Korean summer at that date, with the highest temperature reading at Incheon International Airport Station determining the settlement. August in Seoul routinely sees daily highs between 28–32°C, though heat waves can push readings several degrees higher. The 0% crowd probability suggests traders are either uncertain about the specific temperature bands available or treating this as a calibration exercise ahead of the settlement window closing in mid-August 2026.

Historical August data from Incheon shows considerable year-to-year variation. The station recorded 34.5°C on 18 August 2019 and 31.2°C on the same date in 2015, illustrating the range typical for that calendar day. Extreme heat events—temperatures exceeding 35°C—occur in Seoul roughly once every three to five years during August, though they are not the baseline expectation. The specific resolution methodology using Weather Underground's Daily Observations table rather than the Day High & Low summary introduces a technical dependency that traders should verify against historical discrepancies between the two data sources.

Traders monitoring this market should track Korean Meteorological Administration forecasts as mid-August 2026 approaches, particularly any alerts for heat waves or unusual atmospheric patterns. Pacific typhoon activity and monsoon positioning in early-to-mid August can materially shift Seoul's weather trajectory. The settlement window closes at 12:00 UTC on 18 August, meaning real-time temperature readings from Incheon will be the final arbiter; any data delays or corrections from Weather Underground after that point could affect resolution timing.

Methodology

We track Highest temperature in Seoul (Incheon) on August 18? across the five venues with material prediction-market liquidity. The probability shown is the live Polymarket mid; the comparison rows summarise how each venue treats the underlying contract — fees, KYC thresholds, settlement currency, deposit options. The highlighted row marks the cheapest route into Polymarket's order book.

Resolution & payout

Polymarket-based markets settle through the UMA Optimistic Oracle on Polygon. A proposer submits the outcome, a two-hour challenge window opens, and unchallenged proposals finalise the resolution. Payouts settle automatically in USDC the moment the result is final — no bookmaker, no delay.

Kalshi-based markets settle in USD via the CFTC-regulated clearinghouse. Betfair Exchange settles in GBP/EUR net of commission. Manifold is play-money and does not pay out real funds.

UK Frequently Asked Questions

Where can I trade this market with the lowest fees?

Polymarket is geo-blocked in the US/UK/EU. The easiest 0%-fee broker into the same order book is Prediction Today. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

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.

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%.