Highest temperature in Seoul on June 29?

Platform comparison

Market context

The underlying event is the peak daytime temperature recorded at Incheon International Airport on 29 June 2026, which will determine whether the market settles as a "YES" for the highest temperature exceeding the current threshold. A programmatically inclined trader would treat this as a weather-forecast arbitrage, feeding real-time Wunderground data into a conditional order bot to execute trades only when the predicted high breaches the strike price. The current crowd-implied probability of 14% suggests the market views an extreme heat spike as unlikely, yet historical precedents indicate Seoul is prone to sudden, record-breaking June spikes.

Historical data frames this probability with caution: while average June highs in Seoul climb from 77°F to 81°F, the city has shattered records multiple times, including a 39.6°C peak in 2018 and a national record of 41.0°C in 2025 across Gangwon province[2][3]. Recent reports confirm South Korea experienced record-breaking June heat in 59 cities last year, with 30 June 2025 marking the hottest June day since 1904[5][8]. These outliers suggest that even a low probability like 14% may understate the risk of a sudden, unseasonal heatwave driven by regional atmospheric shifts.

Traders should monitor the Korea Meteorological Administration’s daily heatwave advisories and the 5-day forecast for Incheon, as dependencies include the position of the North Pacific high-pressure system and incoming moisture from the east. A recent surge in June temperatures across 59 stations, where 59 out of 97 weather stations recorded their highest daily average for June, signals that the atmospheric conditions for extreme heat are already active[8]. Any official announcement of a heatwave warning for Seoul or Incheon would act as a direct catalyst, likely causing the implied probability to spike rapidly as the market recalibrates for an imminent temperature breach.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in Seoul on June 29? across the five venues with material prediction-market liquidity. The probability shown is the live Polymarket mid; the comparison rows summarise how each venue treats the underlying contract — fees, KYC thresholds, settlement currency, deposit options. The highlighted row marks the cheapest route into Polymarket's order book.

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

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 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.

Do I need to KYC for this market?

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