Highest temperature in Seoul (Incheon) on August 19?

Platform comparison

Market context

Seoul's summer weather in mid-August typically peaks in the 28–32°C range, with occasional spikes above 33°C during heat waves. The Incheon International Airport weather station, which serves as the official resolution source for this market, records observations throughout the day; the settlement mechanism explicitly prioritises the Daily Observations table over summary high-low figures, a distinction that matters when intraday temperature swings occur. The 0% crowd probability suggests traders are either absent from this market or pricing in an outcome threshold that sits well above historical norms for the date.

Historical August records for Incheon show that temperatures exceeding 35°C occur in roughly 15–20% of years during peak summer, typically in early-to-mid August rather than the 19th specifically. The South Korean Meteorological Administration publishes seasonal forecasts and heat-wave alerts; traders should monitor their mid-August 2026 outlook, released typically in late July, for any indication of anomalous heat patterns. Recent years have seen increased variability in East Asian summer temperatures linked to Pacific pressure systems, though long-range forecasting beyond six weeks carries substantial uncertainty.

Across platforms, this market's structure reveals important differences in how books handle weather precision. Polymarket and Kalshi both settle on third-party data feeds, but Kalshi's regulatory framework in the US may restrict certain traders' access, whilst Betfair's decimal odds format and Smarkets' commission structure create different effective odds for equivalent probability ranges. The explicit Daily Observations requirement here reduces ambiguity compared to markets relying on summary figures, lowering dispute risk at settlement.

Methodology

We read Highest temperature in Seoul (Incheon) on August 19? 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.