Highest temperature in Seoul on May 22?

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Market context

The highest temperature at Incheon International Airport on 22 May will be set by the day’s warmest hourly reading before the market cut-off. The contract is currently priced at 0% YES, which is far below the sort of outcome suggested by late-May climatology: Seoul’s long-run May highs typically run from the high teens to low 20s Celsius, with occasional warm spells pushing into the upper 20s Celsius. Even allowing for Incheon’s coastal influence and a morning settlement window, a reading in the top bracket is not unusual enough to justify a zero line if conditions turn sunny and calm.

Recent history shows why small forecast changes matter. Visual Crossing’s Seoul history for May recorded a peak of 87.1°F on 14 May 2026, while WeatherSpark shows May highs in Seoul rising through the month from about 20°C to 25°C, with low cloud cover persistence and gradually increasing solar energy. AccuWeather’s monthly guide for Seoul also points to average May highs around 27°C, which is consistent with a moderate tail risk of a much warmer day. Against that backdrop, a 0% market price implies either an assumption that the airport location will stay noticeably cooler than central Seoul, or that the settlement window and forecast timing make a late warm-up unlikely. That is a sharper view than the broad climatological consensus.

Traders should watch the Korea Meteorological Administration short-range forecasts and the day’s actual hourly progression at Incheon, especially whether skies clear and winds ease after any early rain or marine layer. The main catalyst is not a scheduled announcement but the local synoptic setup: advection from the mainland, cloud break-up, and sea-breeze timing can shift the day’s maximum by several degrees. With settlement ending at 12:00 UTC, the market is effectively judging the morning-to-early-afternoon peak in Korea, so any forecast update showing a faster warm-up before midday local time would matter more than the full-day high implied by general monthly averages.

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

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.

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 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.

Do I need to KYC for this market?

Not under $1,500 of lifetime trading volume. Above that threshold, PolyGram 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.