Highest temperature in Seoul on June 21?

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Market context

Polymarket is pricing the contract for the highest temperature at Incheon International Airport Station in a very compressed range: the current front-runner is **27°C** at 37%, with **26°C** next at 29%, while the market also shows meaningful volume further down the ladder, including **24°C** and lower outcomes.[1] The implied read-through is that traders expect a warm but not extreme late-June day, with the on-chain position settled in USDC on Polygon via conditional tokens once Wunderground’s daily high for RKSI is finalised.[1]

That pricing sits against a seasonal backdrop that usually favours steadily rising temperatures through June in South Korea. One June climate guide puts average daytime temperatures around **24°C** for the month, rising from about **23°C** at the start to **26°C** by the end, with humidity and rainfall also increasing as the monsoon period approaches.[2][3] For a weather contract like this, that makes the middle outcomes easier to justify than an outsized spike: a clear, sunny spell can push the day higher, but cloud cover, rain, or coastal influence around Incheon can keep the airport reading below the warmest city-centre expectations.

A trader should watch the short-range forecast from the Korea Meteorological Administration, any updates on cloud cover and rain bands, and whether nearby warm-air advection reaches north-western Seoul late in the day.[5] Because settlement depends on the highest observed temperature in the Wunderground history page for Incheon Intl Airport Station, the key practical issue is not the forecast high alone but whether the station records its peak during a brief afternoon warm-up before showers or sea-breeze cooling arrive.[1]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

Methodologically we separate two layers: the live probability (Polymarket mid-price) and the platform attributes (fee, KYC, settlement currency, payment rails). The odds column is filled only where we have clean data — that avoids the made-up numbers that get a network demoted when search engines cross-check against the source venue.

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?

On Kalshi UK, which mirrors the Polymarket order book at 0% fees. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

Is this market available outside the US?

Kalshi UK is available in most jurisdictions where Polymarket isn't directly accessible. Polymarket itself is geo-blocked in the US/UK/EU. Always check local regulations.

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 it cost to trade on Kalshi UK?

Zero. Kalshi UK routes every order to the live Polymarket order book; the only cost is the Polygon network fee, typically under $0.01 per transaction.

Do I need to KYC for this market?

Not under $1,500 of lifetime trading volume. Above that threshold, Kalshi UK triggers a quick verification flow that finishes in minutes.