Highest temperature in Seoul on June 29?

Platform comparison

Market context

On 29 June 2026, the Incheon International Airport Station will record its peak temperature, a single data point that determines whether the market settles on the higher range. The crowd currently assigns a 21% probability to the “YES” outcome, implying the consensus expects temperatures to stay below the threshold. Historically, Seoul’s June highs average between 25°C and 29°C, rarely exceeding 31°C, though 2024 saw record-breaking June heat across 59 cities in South Korea, with Incheon hitting 25.9°C on 29 June—the highest ever for that date since 1907[7]. Even so, the all-time Korean heat record of 41.0°C occurred in Hongcheon in August, not June, and Seoul’s own peak of 39.6°C was also an August event[2][4]. This suggests the threshold is likely set high, making the 21% YES probability potentially undervalued if an early heat spike mirrors the 2024 anomaly.

Traders should monitor the Korea Meteorological Administration’s mid-August forecast, which currently predicts a 60% chance of above-average temperatures, but more immediately, watch for any sudden shifts in the East Asian monsoon or early summer heatwave announcements from the National Weather Service[1]. While no official June heatwave has been declared yet, the 2024 record-breaking June heat in South Korea was driven by a persistent high-pressure system that trapped warmth over the capital region[7]. If similar conditions emerge in the coming days, the Incheon station could breach the threshold, turning the 21% probability into a contrarian value spot. The settlement window closes at 12:00 UTC on 29 June, so real-time Wunderground updates for Incheon will be the definitive catalyst, with no room for post-settlement adjustments[2].

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

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.

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 Who Will Win 2026. 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.

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.

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.

How reliable are the quoted odds?

The YES/NO percentages are the live mid-prices of the Polymarket order book. On deep markets they move every few seconds; on thinner ones you'll see short plateaus.