Highest temperature in Seoul on July 8?

Platform comparison

Market context

The underlying event is the peak heat recorded at Incheon International Airport on 8 July 2026, which will determine the market resolution for Seoul’s highest temperature. With the crowd-implied probability of a “YES” outcome sitting at 0%, the consensus firmly expects the temperature to fall outside the favoured range, likely due to an anticipated heatwave pushing readings well beyond typical early-July norms. Historical data frames this as a clear underdog scenario: Seoul reached 37.8°C on 8 July in a record-breaking early-July spike, the highest in 117 years, while Hongcheon hit 41°C in 2018, and meteorologists warn this summer could be Korea’s hottest yet, with temperatures potentially soaring past 40°C[1][2][4].

Traders should monitor real-time Wunderground updates for Incheon Airport, as the resolution source is explicitly tied to this station’s daily peak, not Seoul city centre averages. The critical catalyst is the ongoing heatwave advisory, now upgraded to a warning across most regions, with Seoul hitting 37.1°C on Tuesday—the highest July temperature since 1908—suggesting the 8 July peak could exceed 38°C[2]. Contrarian value may sit in betting against the 0% implied probability if the market underestimates the intensity of the current tropical night streak, which has already broken a century-old record with overnight temperatures above 25°C for 22 consecutive hours[8]. The settlement window ends at 12:00 UTC on 8 July, so the final reading must be captured before midday, making the afternoon peak irrelevant for resolution.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in Seoul on July 8? 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

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

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 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.

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.