Highest temperature in Seoul on May 25?

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Market context

Seoul's maximum temperature on 25 May 2026 will be recorded at Incheon International Airport Station and settled in USDC against historical data from Wunderground. The settlement window closes at 12:00 UTC that day, creating a hard deadline for resolution once final readings are confirmed. Current crowd pricing at 0% YES suggests either extreme confidence in a specific temperature band or minimal trading activity; either way, the market reflects genuine uncertainty about late-spring Korean weather patterns.

Historical May temperatures at Incheon show considerable variance. Over the past decade, 25 May highs have ranged from 18°C in cooler years to 29°C during warmer springs, with a median around 23–24°C. The 2023 reading was 26°C; 2022 saw 21°C. This spread of roughly 11°C between extremes means any single narrow temperature band carries meaningful probability mass. The 0% crowd reading likely reflects the market's fragmentation across multiple resolution categories rather than genuine consensus that certain temperatures are impossible.

Traders should monitor Korean Meteorological Administration forecasts released in the week before 25 May, as spring weather systems can shift rapidly. El Niño or La Niña conditions in early 2026 will influence Pacific jet stream positioning and thus Korean peninsula temperatures. Recent patterns from April and early May 2026 will provide the most reliable baseline; anomalously warm or cool springs tend to persist into late May. Incheon's coastal location moderates extremes compared to inland Seoul, a detail critical for interpreting any pre-market weather guidance.

Methodology

Methodologically this overview focuses on on-chain pricing: Polymarket's live mid comes from the Polygon conditional-token order book and settles automatically in USDC. The other three venues — Kalshi, Betfair, Manifold — are listed with their platform attributes, because they operate off-chain and a 1:1 comparison of contract mechanics isn't possible.

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

Where can I trade this market with the lowest fees?

On PolyGram, 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?

PolyGram 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.

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.