Highest temperature in Seoul on June 21?

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Market context

The day’s outcome will be set by the **highest air temperature at Incheon Intl Airport Station** recorded on 21 June, not by an average or the 12:00 UTC snapshot, so an automated tracker should pull the daily high from Wunderground’s history page and map it into the market’s Celsius bands. In June, Seoul typically sees highs rising through the month, with average daily highs around 25–27°C and only limited room before the more extreme upper tail becomes relevant.[2]

A 0% crowd-implied price is usually a sign of a very weak or stale market rather than a literal impossibility, so the practical question is whether the weather setup can generate a number that falls into one of the listed ranges. Recent history shows that June can already produce very warm readings in the Seoul area: Visual Crossing’s Seoul history page shows a 2026-06-19 high of 91°F, which is about 33°C, while WeatherSpark says June highs in Seoul can rarely exceed 87°F, or about 31°C.[5][2] That makes the upper bands mechanically possible if conditions are hot enough, even if the market is currently priced as if they are not.

For traders using conditional orders or bots, the useful catalysts are synoptic weather changes rather than scheduled headlines: shifts in the East Asian summer pattern, stronger-than-expected sunshine, or a weak sea breeze can move the day’s maximum into a higher bucket. The source is a single station history entry on Wunderground, so the cleanest programmatic workflow is to watch the station page near local afternoon peak heating, compare the reported maximum to the market’s Celsius intervals, and avoid treating nearby Seoul-area readings as a substitute because resolution is tied to Incheon Intl Airport Station.[1]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page reviews Highest temperature in Seoul on June 21? across five venues. We show live odds for Polymarket-based markets (sourced from the Polygon order book); for other venues we list platform attributes, since the comparable contracts are not exposed via a public API on every venue. Every CTA points at Polymarket App UK — the application we operate, where you trade directly against the Polymarket order book at 0% fees.

Resolution & payout

Settlement runs on-chain. Polymarket's contract logic separates YES and NO shares as conditional tokens; at resolution the winning share lifts to $1.00 and the losing one to $0. The outcome input comes from the UMA Optimistic Oracle, which secures against bad resolution with a bond + dispute window.

Once finalised, the smart contract pays USDC to the holders' wallets within minutes — no withdrawal fees beyond Polygon network gas. Kalshi settles in USD via CFTC clearance, Betfair in account currency net of commission, Manifold in play-money mana with no cash-out.

FAQ

Where can I trade this market with the lowest fees?

On Polymarket App 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?

Polymarket App 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.

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 does it cost to trade on Polymarket App UK?

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

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.