Highest temperature in Seoul on July 18?

Platform comparison

Market context

Seoul's weather on 18 July 2026 will be measured by the highest temperature recorded at Incheon International Airport Station that day, with settlement determined by Wunderground's historical weather database. The market currently prices this contract at 0% YES across all temperature ranges, reflecting either a technical issue with market initialisation or extreme confidence that no specific bracket will resolve. Traders are pricing conditional tokens on Polygon against USDC, where each outcome token represents a discrete temperature band and only one resolves to 1 USDC at settlement.

Mid-July in Seoul typically falls within the peak summer monsoon season, with historical highs clustering between 28–32°C at Incheon. The airport station's readings tend to run slightly cooler than central Seoul due to proximity to coastal influences, though heat domes have periodically pushed readings above 33°C during exceptional years. The 0% pricing suggests either that the market's outcome brackets are misaligned with expected conditions, or that liquidity has not yet formed around any particular range, making this a potential arbitrage opportunity if traders believe standard summer temperatures will occur.

The key variable is whether a heat wave or tropical system affects the Korean peninsula in mid-July 2026. South Korea's Meteorological Administration typically issues extended forecasts 10 days ahead, with updates becoming more precise as the date approaches. Monsoon activity and upper-atmospheric pressure patterns in late June will signal whether conditions favour above-normal or near-normal temperatures. Traders should monitor KMA advisories and regional weather models from early July onwards, as sudden shifts in jet stream positioning can materially alter Seoul's thermal profile within a 48-hour window.

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

Polymarket-based markets settle through the UMA Optimistic Oracle on Polygon. A proposer submits the outcome, a two-hour challenge window opens, and unchallenged proposals finalise the resolution. Payouts settle automatically in USDC the moment the result is final — no bookmaker, no delay.

Kalshi-based markets settle in USD via the CFTC-regulated clearinghouse. Betfair Exchange settles in GBP/EUR net of commission. Manifold is play-money and does not pay out real funds.

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 PolyGram. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

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.

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.