Highest temperature in Seoul on June 25?

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Active sub-markets

Market context

On 25 June 2026, the highest temperature recorded at Incheon International Airport will determine the outcome of a prediction market tracking Seoul’s peak heat, with the current crowd-implied probability of a “YES” result sitting at 0%. This reflects a market consensus that temperatures will not exceed the threshold in question, likely anchored in historical averages where June highs in Seoul typically range between 25°C and 31°C, rarely surpassing 33°C[1][7].

Historically, Seoul has seen extreme heat, including a record of 37.8°C in early July 2023, yet June 25 remains cooler than peak summer days[8]. South Korea’s hottest June ever occurred in 2025, with an average of 22.9°C, suggesting a warming trend but not yet a pattern of June extremes exceeding 35°C[5]. Incheon, slightly cooler than central Seoul due to coastal influence, further reduces the likelihood of record-breaking highs on this date[1].

Traders should monitor the Korea Meteorological Administration’s daily forecasts and any sudden shifts in monsoon patterns or high-pressure systems that could elevate temperatures. Recent reports note South Korea’s increasing heat frequency, with 41.0°C recorded in Hongcheon in 2023, though this remains an outlier for Incheon in June[2]. As platforms like Polymarket, Kalshi, and Betfair diverge on fee structures and KYC requirements, this market highlights how implied probability models on some exchanges may understate tail risks compared to decimal odds systems elsewhere.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We read Highest temperature in Seoul on June 25? from four platform perspectives: Polymarket (on-chain CLOB), Kalshi (CFTC-regulated exchange), Betfair Exchange (sports book exchange), Smarkets (peer-to-peer betting exchange). Polymarket's live quote comes directly from the Polygon order book; the other three are listed with their platform attributes — fees, KYC, settlement currency, payment options — because a 1:1 contract comparison without API access would be guesswork.

Resolution & payout

Settlement is the biggest difference between the four platforms: Polymarket on-chain in USDC (instant), Kalshi USD via CFTC (T+1), Betfair and Smarkets in local currency via bank withdrawal (T+1 to T+3). Polymarket Alternative routes every trade directly into Polymarket's on-chain settlement, which is why payouts land fastest.

FAQ

Where can I trade this market with the lowest fees?

On Polymarket Alternative, 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?

Polymarket Alternative 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, Polymarket Alternative 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.