Highest temperature in Seoul on July 9?

Platform comparison

Market context

On 9 July 2026, Seoul will experience its peak daytime heat at the Incheon International Airport station, a critical metric for traders assessing whether the temperature breaches specific Celsius thresholds. Current crowd-implied probability sits at 0% for the "YES" outcome, suggesting the market expects temperatures to remain within a lower range, despite July historically being South Korea’s hottest and most humid month.

Historical data frames this probability with nuance: Seoul’s July averages hover between 25–30°C, with midday highs often reaching 30°C and humidity pushing "feels like" temperatures above 34°C[1][2]. However, record-breaking early July heat has occurred, with Seoul hitting 37.7°C in 2023—the highest in 117 years of records[7]. Recent climate shifts have also increased "tropical nights" where overnight temperatures stay above 25°C, indicating a warming baseline that could challenge the 0% implied probability if a heatwave coincides with the settlement date[5].

Traders must monitor the Korea Meteorological Administration’s short-range forecasts for July 8–9, as a sudden heatwave could rapidly alter expectations[4]. The monsoon season (Jangma), typically ending mid-July, may bring short but heavy rainfalls that temporarily suppress temperatures, though humidity often retains warmth overnight[1]. Divergence between platforms like Polymarket (decimal odds) and Kalshi (implied probability) could create arbitrage opportunities if one book adjusts faster to forecast updates, while fee structures and KYC requirements further influence liquidity depth on this specific weather event[1].

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page compares Highest temperature in Seoul on July 9? 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 Kalshi 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

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.

What does Polymarket cost vs Kalshi?

Polymarket: 0% fees, only Polygon network costs (~$0.01/trade). Kalshi: up to 7% per trade plus spread. For high-frequency traders, Polymarket is dramatically cheaper.

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 supports Klarna/SOFORT?

Directly: none. Polymarket accepts only USDC on Polygon. Kalshi 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.