Highest temperature in Seoul on June 29?

Platform comparison

Market context

The underlying event is the highest temperature recorded on 29 June 2026 at Incheon International Airport, the official proxy for Seoul’s heat, which will determine whether the market resolves to the “YES” outcome. Current crowd-implied probability sits at 18% YES, suggesting traders view an extreme heat spike as unlikely but not impossible. Historically, Seoul’s June highs climb steadily from 77°F to 81°F, rarely exceeding 87°F, though the nation has shattered records: Hongcheon hit 41.0°C in 2023, and Seoul itself reached 39.6°C in 2018, topping its prior record of 38.4°C[2][3]. Even more recently, 59 South Korean cities recorded record-breaking June heat in 2025, with 30 June marking the hottest June day since 1904[5]. These outliers frame the 18% probability as a cautious bet on a repeat of such anomalies rather than a baseline expectation.

A programmatically-minded trader would monitor real-time Wunderground feeds for Incheon’s hourly peaks, cross-referencing with Korea Meteorological Administration advisories on heatwave declarations and monsoon front positions. The key catalyst is the timing of the East Asian monsoon’s retreat; delays can trap humid air and amplify temperatures, while early progression may cool the region. Recent news confirms South Korea is already bracing for deadly heatwaves, with all-time records set amid rising temperatures[7]. Traders should also watch for official announcements on air quality alerts and emergency cooling schedules, as these often precede or accompany extreme heat days. Given the settlement window ends at 12:00 UTC on 29 June, any late-morning spike in Incheon’s readings could decisively shift the outcome, making minute-by-minute data ingestion essential for conditional order strategies.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page is a comparison snapshot: one live quote, four reference venues with their key attributes, and a single execution path — every trade button routes to Kalshi Fees, which mirrors the Polymarket order book directly.

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 Kalshi Fees. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

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.

What does Polymarket cost to trade?

Polymarket itself charges 0% — the only cost is the Polygon network fee, typically under $0.01 per transaction. Off-chain venues like Kalshi or Betfair charge 2-7% commission.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like Kalshi Fees trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.