Highest temperature in Seoul on July 4?

Platform comparison

Market context

Seoul’s July 4 high temperature hinges on whether the day reaches exactly 29°C, a specific bracket within a historically wide early-July range where highs typically cluster between 27°C and 31°C. The Korea Meteorological Administration confirms that early July temperatures rarely fall below 27°C or exceed 31°C, yet the 29°C mark remains a minority call despite leading the fragmented field at 30.5% implied probability on Lines.com. This contrasts sharply with the current crowd-implied probability of 0% YES on the target prediction market, suggesting a significant divergence where one platform treats 29°C as a plausible one-in-three outcome while the other dismisses it entirely. Analyst consensus leans toward the NO side, noting that six other temperature brackets share the remaining probability, meaning no single outcome commands a majority.

Traders should monitor the Korea Meteorological Administration’s updated forecasts released before the noon KST resolution window, as thin volume below $1M allows prices to shift sharply on minor data updates. Recent records show Seoul hit 37.7°C in an early July spike 117 years ago, and the nation recorded its second-hottest July since 1973 with an average of 27.1°C, indicating that extreme heat events are possible but not guaranteed for this specific date. The North Pacific high-pressure system continues to drive hot, humid conditions, with temperatures occasionally soaring to 35°C, yet the specific 29°C bracket remains a narrow target within this volatile window. Watch for any announcements regarding tropical night streaks, as overnight temperatures above 25°C for 22 consecutive days have recently broken century-old records, potentially influencing daytime highs.

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Methodology

This page reviews Highest temperature in Seoul on July 4? across five venues. The live probability is the Polymarket mid-price, sourced directly from the on-chain Polygon order book; the comparison columns benchmark each venue on fee structure, KYC, settlement currency and payment rails. Every CTA routes to Best Prediction Markets, which mirrors the Polymarket order book at 0% fees.

Resolution & payout

Settlement runs on-chain. Polymarket's contract logic separates YES and NO shares as conditional tokens; at resolution the winning share lifts to $1.00 and the losing one to $0. The outcome input comes from the UMA Optimistic Oracle, which secures against bad resolution with a bond + dispute window.

Once finalised, the smart contract pays USDC to the holders' wallets within minutes — no withdrawal fees beyond Polygon network gas. Kalshi settles in USD via CFTC clearance, Betfair in account currency net of commission, Manifold in play-money mana with no cash-out.

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 Best Prediction Markets. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

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.

What's the difference between YES and NO shares?

A YES share pays $1.00 if the event happens, $0 otherwise. A NO share pays $1.00 if the event doesn't happen. The market price between 0¢ and 100¢ is the implied probability.

What does Polymarket cost to trade?

Polymarket itself charges 0% — the only cost is the Polygon network fee, typically under $0.01 per transaction. Off-chain venues like Kalshi or Betfair charge 2-7% commission.

How reliable are the quoted odds?

The YES/NO percentages are the live mid-prices of the Polymarket order book. On deep markets they move every few seconds; on thinner ones you'll see short plateaus.