Highest temperature in Seoul on July 2?

Platform comparison

Market context

The highest temperature recorded at Incheon International Airport on 2 July 2026 will determine the outcome of this Polymarket contract, which currently prices the 28°C bracket at 39% probability, with 27°C trailing at 26%[1]. Despite the crowd-implied 0% chance for a "YES" outcome in the abstract title, the on-chain mechanics on Polygon using USDC and conditional tokens reflect a market actively betting on mid-to-high 20s Celsius, not a definitive cold snap.

Historical patterns for Seoul in July consistently place daytime highs between 25–30°C, with typical midday anchors near 27°C and occasional peaks nudging 30°C[2]. The summer monsoon season (Jangma) has already begun, with rain spreading across southern Korea while Seoul remains hot and humid through the weekend[3]. This humidity elevates the "feels like" temperature, making 28°C a statistically plausible and frequently observed high rather than an outlier, aligning with the current frontrunner probability.

Traders should monitor the Korea Meteorological Administration’s short-range heatwave forecasts and the timing of the monsoon front’s northward movement, as sudden rain windows of 60–90 minutes can temporarily suppress peak temperatures[2][7]. The resolution source is Wunderground data for Incheon Airport, so any discrepancy between Seoul city forecasts and airport-specific readings could shift the outcome[1]. With the settlement window ending 2026-07-02T12:00:00Z, the next 6 hours of real-time weather updates will be the critical catalyst for price action.

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

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.

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.

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.