Highest temperature in Seoul on May 22?

Platform comparison

Active sub-markets

Market context

The event is the day’s maximum temperature at Incheon International Airport, measured in degrees Celsius and fixed by the Wunderground history page once 22 May is complete. Seasonal context points to a mild late-spring day rather than an extreme one: Seoul’s May averages are typically in the low 20s Celsius, with WeatherSpark showing daily highs around 68–77°F across the month and AccuWeather’s May profile for Seoul indicating highs around 81°F and lows around 62°F. In that setting, a zero-implied-probability contract is consistent with a market expecting the winning band to sit close to the mid-20s Celsius, but airport readings can differ from city-centre weather and coastal winds can cap the peak.

For comparable cases, late-May temperature markets in the Seoul/Incheon area usually settle within a narrow band unless there is an unusual warm surge or an early-season frontal system. The practical read-through is that a single hot afternoon can move the outcome one bracket higher, while morning cloud, sea breeze, or showers can keep the maximum down. Because settlement uses the airport station’s recorded high, traders should focus on the station forecast rather than broader Seoul averages, and on whether the day’s warming is concentrated before or after local midday.

For accessibility and regulation, the same market may be available differently depending on location: German-facing users can run into GlüStV restrictions that limit or block access to event contracts, while US persons face the broader reach of the CFTC, which has taken a strict view of certain binary-event products. On the platform side, “no-KYC up to $1,500” generally means a user may be able to open and use the market with lighter identity checks until that threshold is reached, after which fuller verification is typically required; that affects ease of entry, not the settlement rules.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in Seoul on May 22? on the five venues with material liquidity for prediction markets. Live odds come from the Polymarket Polygon order book — the only source that ships real-time data under an open licence. For Kalshi, Betfair and Manifold we list platform attributes (fee, KYC, settlement, payment) instead of fabricated odds, because their APIs use non-comparable contract definitions.

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?

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 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.