Highest temperature in Seoul on June 21?

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Market context

Seoul’s early-summer maximum is usually comfortable rather than extreme, but June has enough heat and humidity for a warm afternoon spike if sunshine holds. June averages in Seoul are typically around the low-to-mid 20s Celsius, with daytime highs often near 26–28°C and a gradual rise in heat and moisture as the month progresses towards the monsoon period.[1][2][3]

A 0% crowd-implied probability for a **YES** outcome leaves the market priced as if a qualifying temperature band is impossible, which is a strong claim for a late-June Korean weather contract. Historical June patterns suggest the key risk is not a cold day, but a modest overshoot into a warmer range if the air mass turns sunny and humid; comparable guidance places Seoul’s June highs broadly in the 26–28°C area, with occasional hotter days above that.[1][2][4]

For traders, the main catalyst is the actual airport observation published on Wunderground for Incheon Intl Airport Station, since settlement depends on the day’s highest recorded temperature there rather than a citywide forecast.[6] In practice, the market will track the morning and midday evolution of regional cloud cover, rainfall timing, and any shift in the Korean monsoon pattern, while broader risk appetite may matter indirectly through BTC and ETH flows only if the contract is being used as a small weather hedge alongside crypto exposure.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page reads Highest temperature in Seoul on June 21? on-chain. Polymarket's quote comes directly from the Polygon order book — the only comparable venue with on-chain settlement. Kalshi (USD, off-chain), Betfair (GBP/EUR, off-chain) and Manifold (play-money) are listed for comparison. Every CTA routes to BTC Prediction, which mirrors the Polymarket order book directly.

Resolution & payout

Settlement is on-chain via UMA Optimistic Oracle. A proposer posts the outcome with a bond, a two-hour dispute window opens, then the smart contract lifts winning conditional tokens to 1 USDC and sends payments to holders' wallets automatically. No withdrawal fees beyond Polygon gas.

Off-chain venues (Kalshi, Betfair, Smarkets) settle in local fiat through bank-side clearing — faster than SWIFT, slower than on-chain. Manifold pays no real cash.

FAQ

Is this market available outside the US?

BTC Prediction 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'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?

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