Highest temperature in Seoul on July 31?

Platform comparison

Market context

Seoul’s temperature market is really a bet on the day’s *peak* at Incheon Intl Airport Station, not on the capital’s citywide feel. The current crowd price of 0% YES is hard to reconcile with the live weather context: AccuWeather’s July forecast for Seoul shows highs in the low-to-mid 30s °C, while Yonhap reported the Korea Meteorological Administration expected heatwave conditions to continue, with Seoul around 34°C and the broader country seeing apparent temperatures above 35°C.[1][4]

Historically, late-July Seoul is warm enough that a high in the low 30s °C is normal rather than exceptional, and WeatherSpark says July highs in Seoul typically rise into the mid-80s °F, with July 31 among the clearest days of the month.[18] That matters because this market settles on the highest recorded temperature for the full day at Incheon, so even a brief afternoon spike can matter more than the morning reading currently around the mid-to-high 20s °C.[4] On Polymarket, the crowd-implied probability is the clearest signal; on Kalshi and Betfair, traders often see the same weather view through decimal pricing or contract prices, while Smarkets typically makes the fee and net-return comparison easier to read upfront. KYC and access also differ: Betfair and Smarkets are generally more jurisdiction-dependent, while Polymarket access can be broader but still varies by location and compliance rules.

For catalysts, the main watchpoints are the afternoon heating profile, any rain bands that cap the high, and whether the KMA’s heatwave guidance changes before the settlement window closes. Yonhap noted possible sudden showers of up to 80 mm in parts of the Seoul area, which would be the main near-term brake on the temperature reaching a higher band.[4] If the day stays clear and humid, the market can move quickly as the airport station approaches its daily maximum, whereas any cloud cover or rainfall would reinforce the current low YES pricing.

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 Polymarket Alternative, 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

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 is accessible globally?

Polymarket is geo-blocked in the US/UK/EU. Kalshi is US-only. Betfair and Smarkets are UK-restricted. Polymarket Alternative 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.