Highest temperature in Seoul on July 17?

Platform comparison

Market context

Seoul is bracing for its peak July heat as the Incheon International Airport station records the day’s maximum temperature, with the market currently pricing a 0% chance of any outcome above the consensus range. The crowd has locked in 31°C as the frontrunner at 76% probability, while 32°C or higher sits at 22%, reflecting tight clustering around 28–29°C due to ongoing East Asian monsoon conditions bringing widespread cloud cover and scattered showers through mid-week[1].

Historically, Seoul’s July highs have rarely breached 32°C without a sustained heatwave, and the 2025 event that marked the hottest July since 1908 saw temperatures hold just below that threshold before cooling by the 16th[2]. This pattern suggests the current 0% implied probability for extreme outcomes is not overconfident; the monsoon’s dampening effect acts as a natural underdog, making contrarian bets on 32°C+ a low-value spot unless the cloud cover breaks unexpectedly.

Traders should monitor the monsoon’s trajectory and any sudden shifts in cloud density, as these are the primary catalysts that could push temperatures toward the 32°C+ underdog. No official announcements or scheduled interventions are expected, but real-time updates from Wunderground’s daily history for RKSI will determine settlement, and any revision to temperatures before the next day’s first datapoint remains possible[1]. The value lies in waiting for a clear break in the monsoon rather than front-running the current consensus.

Sources: 1 · 2

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.

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 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.