Highest temperature in Seoul on June 29?

Platform comparison

Market context

The underlying event is the peak of Seoul’s June heat, with the market betting on whether the Incheon Intl Airport Station will record a temperature in the highest range on 29 June 2026. Historically, Seoul’s June highs climb from 77°F to 81°F, rarely exceeding 87°F, though record-breaking June heat has struck 59 cities in South Korea, with 29 June 2024 hitting 25.9°C and surpassing the 1907 benchmark for the month[3][7]. The all-time Korean heat record of 41.0°C was set in Hongcheon, but Seoul itself reached 39.6°C in 2018, showing the capital can spike well above average during extreme events[2][4].

With the crowd-implied probability at 21% YES, the consensus leans against a top-range hit, yet value may sit with contrarian traders if monsoon delays or dry-air surges push temperatures higher. Traders should watch the Korea Meteorological Administration’s forecasts for mid-August, which currently suggest a 60% chance of hotter-than-average conditions, and monitor any early heatwave announcements from the National Weather Service[1]. Recent news confirms South Korea is already experiencing record-breaking June heat, with 25.9°C on 29 June 2024 marking the highest June temperature since observations began[7]. The settlement window ends at 12:00 UTC on 29 June 2026, so real-time Wunderground data from Incheon will be the decisive factor.

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. 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.

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.