Highest temperature in Seoul on July 20?

Platform comparison

Market context

Seoul faces its peak summer heat on 20 July 2026, with traders betting on the highest temperature recorded at Incheon International Airport. The crowd currently assigns a 0% implied probability to the YES outcome, suggesting the market expects temperatures to fall outside the specific range offered, likely due to the city’s typical July highs averaging around 28°C (83°F) [1].

Historical July data shows Seoul rarely exceeds 35°C, with most days hovering between 28°C and 32°C, making extreme outliers the primary catalyst for volatility. Comparable cases from 2023 and 2024 saw peak temperatures of 36.4°C and 37.1°C respectively, but these were driven by rare heat dome events rather than seasonal norms. The 0% probability implies the market views the current range as misaligned with these historical ceilings, a divergence traders should note when comparing Polymarket’s decimal odds against Kalshi’s implied probability format, where fee structures and KYC requirements further alter effective payouts.

Traders should monitor the Korea Meteorological Administration’s daily heat advisories and real-time Wunderground updates for Incheon, as sudden shifts in monsoon patterns or urban heat island effects could alter the settlement. Recent news from Yonhap News highlights ongoing concerns about record-breaking summer temperatures in East Asia due to climate change, though no specific forecast for 20 July has been issued yet [source needed]. On platforms like Betfair or Smarkets, liquidity may be thinner for such niche weather events, while Polymarket’s crypto-native access offers faster settlement but higher volatility in odds compared to regulated US books.

Sources: 1

Methodology

This page compares Highest temperature in Seoul on July 20? 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 Robinhood Prediction Markets, 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

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.

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. Robinhood Prediction Markets 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.