Highest temperature in Seoul on July 21?

Platform comparison

Market context

Seoul faces its peak summer heat on 21 July 2026, with the market tracking the highest temperature recorded at Incheon International Airport. The crowd-implied probability of a specific outcome sits at 0% YES, suggesting traders view the proposed temperature range as virtually impossible given typical mid-summer conditions. Historical data shows Seoul’s July highs average 28°C, with humidity often reaching 80%, creating a baseline that makes extreme deviations unlikely without a specific weather anomaly [1].

Comparable cases from recent years indicate that temperatures rarely stray far from the 28–32°C band during this period, even during heatwaves. The 0% probability aligns with analyst consensus that the market’s threshold exceeds plausible historical maxima for Incheon, where record highs typically cap near 38°C. Sportsbook lines on similar weather contracts often reflect tighter spreads, but prediction markets here show a stark divergence, implying the crowd sees no credible path to the settlement condition.

Traders should monitor the Korea Meteorological Administration’s daily forecasts and Wunderground’s real-time updates for Incheon, as sudden shifts in monsoon patterns or heat dome formations could alter expectations. Recent reports highlight a 43% chance of rain on average July days, which could suppress peak temperatures if precipitation occurs before midday [1]. No major announcements are scheduled, but the settlement window ending at 12:00 UTC means afternoon heat spikes remain the primary catalyst for any probability shift.

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

At resolution the UMA oracle takes over: a proposer posts the outcome with a bond, any token holder can dispute within two hours. Without dispute the result is accepted and the smart contract distributes USDC instantly.

On Kalshi (CFTC-regulated) resolution runs through their in-house clearing engine in USD. Betfair Exchange settles after match end in the account's local currency. Manifold pays no cash — only its in-platform "mana" currency.

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 Best Prediction Markets. 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'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.

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.