Highest temperature in Seoul on July 3?

Platform comparison

Market context

The highest temperature recorded at Incheon International Airport on 3 July 2026 will determine the outcome of this Polymarket contract, which currently prices the "YES" option at 0% despite Seoul’s typical July heat. On-chain, traders are locking USDC on Polygon to buy conditional tokens, betting on whether the peak temperature will fall into a specific range, yet the market implies near-certainty that the event will not trigger the winning condition.

Historically, July in Seoul sees daytime highs averaging 25–30°C, with occasional spikes nudging 30°C, while humidity often pushes the "feels like" temperature above 34°C[2]. However, the monsoon season (Jangma), active from late June to mid-July, brings frequent showers that suppress peak temperatures, and recent forecasts for 3 July predict mostly cloudy skies with localized thunderstorms and highs of only 28°C in Incheon[3]. This pattern of rain-interrupted heat explains why the crowd-implied probability remains at 0%, as the weather is unlikely to reach the threshold required for the "YES" outcome.

Traders should monitor the Korea Meteorological Administration’s short-range forecasts for heatwave alerts and real-time Wunderground updates for Incheon’s hourly peaks, as sudden clearings could briefly elevate temperatures[5]. A recent AccuWeather report notes July highs can reach 91°F (32.8°C), but the current cloud cover and rain risk in the Seoul metropolitan area make such extremes improbable today[6]. The key dependency is whether the rain clears before midday; if it persists, the temperature will likely stay below the critical range, confirming the market’s current pricing.

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.

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.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like Kalshi UK trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.