Highest temperature in Seoul on July 31?

Platform comparison

Market context

Seoul’s late-July heat is the main driver here, but the market actually settles on the **day’s maximum at Incheon International Airport Station**, not a citywide Seoul reading. That matters because airport observations can diverge from inland neighbourhoods, and on this date the wider region is already in an extreme heat regime: Reuters and Yonhap reported South Korea’s highest-ever temperature of 41.4C in Yangsan on 31 July, while Seoul was also experiencing a prolonged run of tropical nights and some of the warmest overnight conditions on record.[2][7][1]

For historical context, Seoul’s late-July highs are often in the mid-30s, with the city’s all-time record at 39.6C in August 2018 and a July record of 38.4C referenced in climate summaries and past reports.[14][17][3] Incheon has been materially cooler in many past heatwaves; Yonhap’s 2018 coverage put Incheon at 35.2C on a day when Seoul reached 38.3C, underscoring the gap traders should keep in mind when mapping a “Seoul” headline to an airport-based resolution source.[3] A crowd-implied 0% YES on Polymarket signals either a missing contract match or a market that has not been repriced to the weather backdrop; on Kalshi, the same event would usually be shown as a dollar price rather than a probability, while Betfair and Smarkets would display odds and take exchange commissions instead of a market maker spread.

The near-term catalyst is the afternoon temperature path at the airport, driven by the persistence of the current heat dome and the timing of any showers, sea breeze, or cloud cover around the coast. Reuters reported the broader heatwave had already produced three straight days above 40C in parts of the country, so the key question for this contract is less whether Korea is hot and more whether Incheon peaks high enough to land in the settled temperature band before 12:00 UTC.[2][7] Access also differs by platform: Polymarket and Kalshi require account verification in supported jurisdictions, while Betfair and Smarkets depend on local availability and may be unavailable where the user is not KYC-cleared.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page compares Highest temperature in Seoul on July 31? 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

Settlement is the biggest difference between the four platforms: Polymarket on-chain in USDC (instant), Kalshi USD via CFTC (T+1), Betfair and Smarkets in local currency via bank withdrawal (T+1 to T+3). On-chain settlement clears in minutes — the fastest payout path of the four.

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.

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.