Highest temperature in Seoul on May 21?

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Market context

Seoul’s late-May weather is usually mild rather than hot, with average highs around 21–27°C and a typical late-May rise in warmth as the month progresses. WeatherSpark puts May highs in Seoul in a broad band from about 20°C to 25°C, with the chance of a wet day easing from roughly 24% at the start of the month to 21% by month-end. For an airport station reading, that points to a fairly ordinary late-spring profile: a warm afternoon is plausible, but an extreme heat outcome is not the base case.

Historical comparables also suggest the upper temperature range on 21 May is often confined to the low or mid-20s Celsius rather than anything much higher. AccuWeather’s May outlook for Seoul shows daily highs generally between 19°C and 32°C, but the climatology is much narrower than that forecast range implies, and recent mid-May observations in the city have already touched the upper 20s °C only briefly. A 0% crowd-implied YES price fits a market that is effectively pricing the absence of any unusually strong warm spell.

For traders, the key catalyst is the actual afternoon peak at Incheon Intl Airport, which can still be affected by a short warm surge, coastal breeze, or shower cover even if Seoul itself feels pleasant. The market should lean on the final airport history entry once Wunderground locks the day’s data, with any late-day warming most relevant to the upper temperature band. Recent regional forecasts from the Korea Meteorological Administration have pointed to day-by-day variability rather than a sustained heat set-up, so the immediate watchpoint is whether local conditions stay clear and sunny enough to lift the high by a few degrees.

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Methodology

Political prediction markets differ structurally from sports betting: thinner liquidity, longer settlement windows, higher sensitivity to single news events. This page shows the live Polymarket quote for Highest temperature in Seoul on May 21? plus platform attributes for the three reference venues, so you can see at a glance where the deepest market for this question sits.

Resolution & payout

Political markets typically settle on official candidate or agency confirmation. Polymarket uses UMA Optimistic Oracle: a proposer posts the outcome with a bond, the two-hour window opens, then the smart contract pays USDC.

Kalshi settles USD via CFTC clearinghouse, with clearly defined resolution sources (e.g. AP race calls for elections). Betfair settles after the official outcome is registered with the league or agency. Manifold is play-money.

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.

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.

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.