Highest temperature in Seoul on July 21?

Platform comparison

Market context

Seoul faces its peak summer heat on 21 July 2026, with the market betting on whether the Incheon International Airport station will record a temperature within a specific Celsius range. The crowd-implied probability sits at 0% for the current favourite, suggesting the consensus expects conditions to fall outside this narrow band entirely. Historically, mid-July in Seoul brings average highs near 28°C with a 43% daily chance of rain, which often suppresses extreme temperature spikes through cloud cover and precipitation [1]. Comparable cases from recent years show that when rain occurs, peak temperatures rarely breach 32°C, making the current 0% valuation potentially a contrarian signal if forecasts predict a dry, high-pressure spell.

Traders must monitor the immediate 24-hour weather outlook for the Korean Peninsula, specifically any announcements regarding the monsoon front’s position or sudden shifts in high-pressure systems from the Pacific. A dry, stagnant air mass would act as the primary catalyst for temperatures exceeding the implied range, while an active rain front would reinforce the 0% consensus. Recent meteorological schedules indicate that July 2026 could see variable monsoon activity, meaning the timing of the front’s arrival is the critical dependency for this settlement [1]. Value likely sits on the underdog if forecast models show a break in the rain pattern before noon, as the current pricing ignores the possibility of a sudden heat spike driven by clear skies.

Sources: 1

Methodology

We track Highest temperature in Seoul on July 21? 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 Who Will Win. 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 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.