Highest temperature in Seoul on July 7?

Platform comparison

Market context

Seoul on 7 July 2026 faces a critical heat test, with the market betting on whether the Incheon International Airport Station will record a temperature exceeding the implied threshold. The crowd-implied probability sits at 0% YES, suggesting near-universal consensus that the day will remain within normal bounds. Yet, historical data reveals a volatile backdrop: July highs in Seoul typically climb from 81°F to 85°F, rarely dipping below 74°F or surging past 91°F[1]. More strikingly, South Korea recently shattered its all-time heat record at 41.0°C in Hongcheon, while Seoul itself hit 37.7°C in early July 2025—the highest such reading in 117 years[2][7]. This pattern of escalating extremes, including a century-old streak of tropical nights above 25°C, frames the 0% probability as potentially underpriced for a contrarian trader seeking value[6][8].

The catalysts traders must monitor include the Korea Meteorological Administration’s daily heat advisories and any sudden shifts in monsoon moisture, which could either suppress or amplify temperatures. Recent reports confirm that nighttime heat in Seoul has become a persistent issue, with overnight temperatures above 25°C breaking records for 22 consecutive days[8]. While no official announcements have yet flagged an extreme heat event for 7 July, the trend of record-breaking summers—such as South Korea’s second-hottest July since 1973—suggests the consensus may be overlooking latent risk[5]. For the handicapper, the underdog here is the “normal” forecast; value may lie in betting against the 0% line if monsoon delays or dry air masses intensify the heatwave. The market’s dismissal of extreme outcomes ignores the accelerating climate trajectory evident in recent data.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

Methodologically we separate two layers: the live probability (Polymarket mid-price) and the platform attributes (fee, KYC, settlement currency, payment rails). That keeps the comparison honest — a single canonical probability across the row, with the venue-by-venue trade-offs spelt out in the columns next to it.

Resolution & payout

At resolution the UMA oracle takes over: a proposer posts the outcome with a bond, any token holder can dispute within two hours. Without dispute the result is accepted and the smart contract distributes USDC instantly.

On Kalshi (CFTC-regulated) resolution runs through their in-house clearing engine in USD. Betfair Exchange settles after match end in the account's local currency. Manifold pays no cash — only its in-platform "mana" currency.

FAQ

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.

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.