Highest temperature in Seoul (Incheon) on August 5?

Platform comparison

Market context

The decisive event is the **highest temperature reached at Incheon International Airport** on 5 August 2026, with the market settling to the temperature band containing that day’s maximum. In the wider Seoul area, official and media forecasts point to severe heat: SBS says Seoul’s daytime high is expected to reach **38°C**, with hot conditions persisting day and night, while other August outlooks for the city cluster around the low-to-mid 30s rather than anything near freezing.[1][2][12]

That makes the current **0% YES** crowd price look like a platform-lens outlier rather than a clean read on weather risk. On Polymarket, traders usually discuss **implied probability** directly, whereas Kalshi and Betfair more often expose **decimal-style pricing** or exchange odds, so the same view can look numerically different across books; fee treatment also matters, because exchange commissions and market-maker spreads can compress returns versus a cleaner binary contract. For a temperature market like this, the relevant historical guide is that August in Seoul is typically hot and humid, with average highs around the high 20s to low 30s, but extreme heat spikes above 35°C do occur in the region.[16][19]

The main catalyst is whether the heat wave peaks over the airport station specifically, rather than in central Seoul, because airport readings can diverge modestly from city-centre forecasts. Traders should watch for updated Korea Meteorological Administration short-range guidance and any convective showers, since SBS notes showers in parts of the western regions even as the heat warning remains in force.[1][4][12] If the day stays dry and the air mass holds, the upper end of the market’s temperature bands becomes materially more plausible; if cloud, rain, or marine influence limit daytime heating, the settlement could land lower than headline Seoul forecasts suggest.[1][4]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page compares Highest temperature in Seoul (Incheon) on August 5? specifically across Polymarket, Kalshi, Betfair Exchange and Smarkets. The live probability is the Polymarket mid; the comparison columns summarise each venue's fee structure, KYC, settlement currency and payment rails. Every CTA routes to Polymarket Alternative, which mirrors the Polymarket order book at 0% fees.

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

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.

What about Smarkets as an alternative?

Smarkets is a UK betting exchange with a lower default commission (2%) than Betfair. Liquidity on political markets is below Polymarket, comparable to Kalshi. Geo-blocked in many jurisdictions.

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.

Which platform supports Klarna/SOFORT?

Directly: none. Polymarket accepts only USDC on Polygon. Polymarket Alternative offers a fiat on-ramp via Klarna or SOFORT (DE/AT/CH) and converts internally to USDC for the Polymarket order book. T+1 processing.