Highest temperature in Seoul on July 20?

Platform comparison

Market context

Seoul’s highest temperature on 20 July 2026 will be measured at Incheon International Airport, with short-term forecasts pointing to a peak near 28°C as the most likely outcome. Historical data shows July is Seoul’s wettest month, with a 43% daily chance of precipitation and average highs of 28°C, making extreme heat above 32°C uncommon but not impossible [2]. The current crowd-implied probability of 0% YES suggests the market expects the temperature to fall outside the defined “YES” range, likely because the contract’s threshold sits above the forecasted 26–29°C cluster [1].

Traders should monitor real-time updates from Wunderground, the official resolution source, as revisions to recorded temperatures are accepted until the first datapoint for 21 July is published [1]. Key catalysts include any sudden shifts in monsoon activity or unseasonal heatwave announcements from the Korea Meteorological Administration, which could push temperatures beyond the market’s implied range. While no major weather announcements have been issued as of 20 July evening, the high precipitation probability in July means cloud cover and rain could suppress daytime highs, reinforcing the 0% YES probability unless an unexpected heat spike occurs [2].

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

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.

Do I need to KYC for this market?

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

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.