Highest temperature in Seoul on July 5?

Platform comparison

Market context

The underlying event is the peak daytime heat recorded at Incheon International Airport on 5 July 2026, a date that historically sits within Seoul’s most intense summer window. Current crowd-implied probability of 0% for the “YES” outcome suggests the market expects temperatures to fall outside the specific range being traded, yet this stance diverges sharply from historical precedent. Since 1973, Korea’s hottest July occurred in 1994 with an average of 27.7°C, while July 2025 was the second-hottest at 27.1°C[1]. Incheon’s daily highs in July typically climb from 81°F to 85°F, rarely dipping below 74°F or exceeding 91°F[2]. Recent records show Seoul hitting 37.7°C in early July—the highest in 117 years[6], and Hongcheon reaching 41.0°C overall[3]. These figures frame the 0% probability as potentially misaligned with the region’s escalating heat trend.

Traders should monitor the North Pacific high-pressure system’s strength, which drives humid, hot conditions capable of pushing temperatures to 35°C or higher[8]. Key catalysts include official forecasts from the Korea Meteorological Administration and real-time Wunderground data for Incheon, the designated resolution source. Recent reporting confirms South Korea endured record-breaking summer heat in August 2025, with averages 2.9°C above the 1991–2020 baseline[4]. Additionally, July 2025 marked the longest stretch of tropical nights in Seoul for 117 years, indicating heat that lingers well into the night[7]. As settlement closes on 5 July 2026 at 12:00 UTC, any sudden shift in pressure patterns or cloud cover could materially alter the outcome, making live weather feeds essential for accurate cross-platform odds comparison.

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

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 PolyGram. 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.

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 PolyGram trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.