Highest temperature in Seoul on May 22?

Platform comparison

Active sub-markets

Market context

Seoul’s heat peak has effectively been locked in before the noon settlement window, with the market already sitting at 0% YES and no sign of a late-day surge changing the outcome. For a daytime high to clear into the upper buckets, the warming would normally need to arrive early, not after midday; by 18:00 UTC, the relevant observation period is already over. Late-May Seoul is usually mild to warm rather than hot, with typical highs around 21–22°C, so a result near the lower bands is more consistent with seasonal norms than an outlier spike.

That is the useful historical frame here: in recent May weather patterns for Seoul, the first half of the month tends to stay comfortably springlike, and even warmer late-May days often top out in the low-to-mid 20s°C. The market’s 0% YES reading implies traders see little chance of the final recorded high landing outside the currently favoured range once the Incheon airport observation is finalised. In practice, these temperature markets usually hinge on whether afternoon sun, light winds and any dry air can push readings a degree or two higher than forecast.

The main things to watch are the Korea Meteorological Administration’s short-range updates and any last-minute shifts in cloud cover, rainfall chances or wind direction over the Seoul/Incheon area. A clearer, sunnier midday can lift the maximum by a notch, while sea-breeze influence from the west and passing cloud can cap the high below the warmer buckets. The market resolves from the final Wunderground history for Incheon Intl Airport Station, so the only relevant catalyst now is whether the official recorded maximum is revised with a late update before finalisation.

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

At resolution the UMA oracle takes over: a proposer posts the outcome with a bond, any token holder can dispute within two hours. Without dispute the result is accepted and the smart contract distributes USDC instantly.

On Kalshi (CFTC-regulated) resolution runs through their in-house clearing engine in USD. Betfair Exchange settles after match end in the account's local currency. Manifold pays no cash — only its in-platform "mana" currency.

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.

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.

What does it cost to trade on PolyGram?

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

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.