Highest temperature in Seoul on July 4?

Platform comparison

Market context

Seoul’s early July highs typically cluster between 27°C and 31°C, with the 29°C bracket sitting at the centre of this historical range. Yet the market currently prices the chance of hitting exactly 29°C at just 30.5%, meaning traders view it as a minority outcome despite its centrality. The NO side, trading at $0.70, is favoured because six other temperature brackets share the remaining probability, leaving no single outcome with majority support. This fragmented field reflects Seoul’s genuinely wide thermal window in early July, where deviations of ±2°C are common and no single value dominates.

Historically, Seoul has recorded extremes far beyond this range, including 37.7°C in 2023—the highest early July temperature in 117 years of records. Last year, South Korea endured its second-hottest July since 1973, averaging 27.1°C, while a streak of super-hot tropical nights broke a century-old record with overnight temperatures above 25°C for 22 consecutive days. These precedents suggest that while 29°C is plausible, the actual high could easily land in adjacent brackets, especially given the region’s increasing heat volatility.

Traders should monitor the Korea Meteorological Administration’s daily forecasts for July 4, 2026, and watch for updates on the North Pacific high-pressure system, which drives summer humidity and heat spikes in Seoul. Recent reports from Anadolu Ajansı confirm that Seoul reached 37.7°C in 2023, underscoring the potential for sudden extremes. On Polymarket, this contract resolves in USDC on the Polygon network using conditional tokens, with settlement at noon KST on July 4. The current 0% YES probability implies the market expects the high to fall outside the 29°C bracket, likely due to the wide historical variance and recent heat trends.

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Methodology

We track Highest temperature in Seoul on July 4? across the five venues with material prediction-market liquidity. The probability shown is the live Polymarket mid; the comparison rows summarise how each venue treats the underlying contract — fees, KYC thresholds, settlement currency, deposit options. The highlighted row marks the cheapest route into Polymarket's order book.

Resolution & payout

Polymarket-based markets settle through the UMA Optimistic Oracle on Polygon. A proposer submits the outcome, a two-hour challenge window opens, and unchallenged proposals finalise the resolution. Payouts settle automatically in USDC the moment the result is final — no bookmaker, no delay.

Kalshi-based markets settle in USD via the CFTC-regulated clearinghouse. Betfair Exchange settles in GBP/EUR net of commission. Manifold is play-money and does not pay out real funds.

FAQ

Where can I trade this market with the lowest fees?

Polymarket is geo-blocked in the US/UK/EU. The easiest 0%-fee broker into the same order book is Kalshi UK. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

Is this market available outside the US?

Polymarket itself is geo-blocked in the US/UK/EU. Always check the legal status of prediction markets in your jurisdiction before trading.

How does resolution work?

Through the UMA Optimistic Oracle on Polygon: a proposer submits the outcome, a two-hour challenge window opens, and USDC payouts settle automatically once the result is final.

How fast are USDC deposits?

Polygon credits deposits after 12 confirmations — usually under 30 seconds. Withdrawals follow the same path and land back in your wallet within minutes.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like Kalshi UK trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.