Highest temperature in Seoul (Incheon) on August 18?

Platform comparison

Market context

Seoul's peak temperature on 18 August 2026 will be recorded at Incheon International Airport Station and measured against specific resolution criteria on Weather Underground's Daily Observations table. The market settles to a temperature range bracket rather than an exact figure, with the crowd currently assigning zero probability to any outcome—a signal either of extreme uncertainty or insufficient liquidity to establish meaningful pricing.

August in Seoul typically peaks between 28–32°C, though heat waves regularly push readings above 33°C. Historical data from the Korea Meteorological Administration shows that mid-August temperatures have exceeded 35°C in roughly one-third of years since 2010, with 2018 and 2022 recording particularly intense heat events. The distinction between Weather Underground's Daily Observations table and its Day High & Low summary matters operationally: automated resolution systems must query the correct data source to avoid settlement disputes. Traders building conditional orders or bot-based monitoring should test their data feeds against both Wunderground endpoints well before the settlement window closes on 18 August at noon UTC.

Catalysts affecting August 2026 temperatures remain dependent on seasonal patterns and any anomalous weather systems forming in late summer. The Korea Meteorological Administration publishes monthly forecasts and heat advisories; traders monitoring this market should track their mid-August outlook issued in July. Pacific typhoon activity and the position of the North Pacific high-pressure system typically drive Korean peninsula temperatures during this period. Setting up programmatic alerts for Wunderground data updates and KMA advisories will be essential for traders managing positions through the settlement window.

Methodology

Methodologically we separate two layers: the live probability (Polymarket mid-price) and the platform attributes (fee, KYC, settlement currency, payment rails). That keeps the comparison honest — a single canonical probability across the row, with the venue-by-venue trade-offs spelt out in the columns next to it.

Resolution & payout

At resolution the UMA oracle takes over: a proposer posts the outcome with a bond, any token holder can dispute within two hours. Without dispute the result is accepted and the smart contract distributes USDC instantly.

On Kalshi (CFTC-regulated) resolution runs through their in-house clearing engine in USD. Betfair Exchange settles after match end in the account's local currency. Manifold pays no cash — only its in-platform "mana" currency.

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 Polymarket Review UK. 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%.