Highest temperature in Seoul on June 30?

Platform comparison

Market context

The real-world event centres on the highest temperature recorded at Incheon International Airport on 30 June 2026, which will determine the resolution of this prediction market. Historically, Seoul’s June highs climb steadily from 77°F to 81°F, rarely dipping below 68°F or exceeding 87°F, while the nation recently logged its hottest June average since 1973 at 22.9°C[1][4]. Incheon, situated west of Seoul, typically mirrors these trends but can experience slightly moderated peaks due to coastal influence; however, record-breaking heatwaves have pushed nearby areas to 41.0°C, as seen in Hongcheon last year[2]. The current crowd-implied 0% probability for any specific range suggests traders deem the outcome too uncertain or the threshold unattainable under normal conditions, yet recent anomalies like 39.6°C in Seoul in 2018 and 25.8°C average highs in 2024 indicate volatility that defies simple assumptions[6][7].

A power-user approaching this programmatically would monitor Wunderground’s real-time feed for Incheon, cross-referencing with Korea Meteorological Administration advisories and local heatwave alerts. Key catalysts include the scheduled release of the June 2026 climate summary by Yonhap News, which may confirm whether this month continues the trend of record-breaking averages[4]. Traders should also watch for sudden shifts in shortwave solar energy, which is gradually decreasing in June but can spike during clear-sky episodes, and for any official announcements regarding emergency heat protocols in the Gangwon or Seoul regions[1][7]. Recent news from Chosun confirms that 59 cities experienced record June heat, with 30 June marking the hottest day since 1904, reinforcing the need to track daily extremes rather than monthly averages[7]. For conditional order strategies, integrating Wunderground’s API with a bot that triggers alerts when temperatures breach 35°C would provide early signals for position adjustments.

Sources: 1 · 2 · 3 · 4 · 5

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.

FAQ

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 Bot 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.

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.

What's the difference between YES and NO shares?

A YES share pays $1.00 if the event happens, $0 otherwise. A NO share pays $1.00 if the event doesn't happen. The market price between 0¢ and 100¢ is the implied probability.

How fast are USDC deposits?

Polygon credits deposits after 12 confirmations — usually under 30 seconds. Withdrawals follow the same path and land back in your wallet within minutes.