Highest temperature in Seoul on July 10?

Platform comparison

Market context

On 10 July 2026, the highest temperature recorded at Incheon International Airport will determine the outcome of a prediction market where the crowd currently assigns zero probability to any non-minimal range. This real-world event hinges on a single day’s peak heat in a region that has recently experienced unprecedented tropical nights and record-breaking July temperatures across South Korea.

Historical data frames this zero-implied-probability stance as potentially fragile. Seoul reached 37.7°C in early July 2023—the highest in 117 years of records[7], while the nation set an all-time heat record of 41.0°C at Hongcheon in 2023[2]. July 2023 also marked South Korea’s second-hottest July since 1973, with average temperatures nearing 27.7°C[4]. Incheon typically sees July highs between 81°F and 85°F (27–29°C), rarely exceeding 91°F (33°C)[5]. Polymarket’s decimal odds model may understate tail risk compared to Kalshi’s implied probability framework, which often better captures low-probability extremes.

Traders should monitor the Korea Meteorological Administration’s weekly heatwave forecasts and any sudden shifts in monsoon patterns, which could suppress or amplify daytime peaks. Recent reports confirm Seoul endured 22 consecutive nights above 25°C in July 2023, breaking a century-old record for tropical nights[1]. Fee structures diverge sharply: Polymarket charges no KYC but higher withdrawal fees, while Kalshi requires identity verification but offers lower trading costs. Betfair’s spread-based pricing may lag Wunderground’s real-time updates, the official resolution source for this market. Smarkets’ 2% fee cap could favour high-volume traders assessing volatility in Seoul’s microclimate.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We read Highest temperature in Seoul on July 10? 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 mid is the canonical probability; the side-by-side columns benchmark fees, KYC, settlement currency and deposit rails so you can choose the venue that fits your jurisdiction and trade size.

Resolution & payout

Polymarket settles via UMA Optimistic Oracle on Polygon. A proposer posts the outcome with a bond, the two-hour window runs, then the smart contract pays USDC.

Kalshi settles USD through the CFTC-regulated clearinghouse — the cleanest variant, with heavier KYC. Betfair Exchange settles in account currency (GBP/EUR), net of 2-5% commission. Smarkets follows the same model as Betfair with a lower default 2% commission.

FAQ

Polymarket vs Kalshi — which is better?

Depends on your location. Kalshi is CFTC-regulated, US-only with full KYC. Polymarket is global, on-chain, no KYC up to $1,500. Polymarket has ~10x higher liquidity but higher regulatory risk.

Which platform has the deepest liquidity?

Polymarket — by a wide margin. Top markets reach $50-500M volume, Kalshi ~$200M cumulative, Betfair similar. Deeper liquidity means your trade moves the quote less.

Is Betfair a Polymarket alternative?

Only partially. Betfair Exchange is UK-focused with a sports-betting emphasis; they have politics markets but with thinner liquidity than Polymarket. Settlement in GBP/EUR, 2-5% commission on winnings.

Which platform is accessible globally?

Polymarket is geo-blocked in the US/UK/EU. Kalshi is US-only. Betfair and Smarkets are UK-restricted. Robinhood Prediction Markets has a different geo footprint and routes to Polymarket's order book at 0% fees.

Are all these platforms regulated?

No. Kalshi is CFTC-regulated (US). Betfair and Smarkets are UK Gambling Commission licensed. Polymarket operates without explicit regulation — a different risk profile than a regulated sportsbook.